def mtv_to_sf(timetable_str: str) -> dict:
    """
    Given a timetable as a string, return a dictionary with the travel time in minutes 
    from Mountain View to San Francisco for trains 703, 303, and 509.
    
    The timetable string is expected to start with two header lines. The first header line 
    begins with "Station Name" followed by train numbers. In each data row, the final N tokens 
    correspond to N scheduled times (one per train, where N equals the number of train ids in the header),
    and the remaining tokens (after the zone number in the first position) make up the station name.
    
    If a station time is "--" (missing), then that train’s result is set to None.
    """
    import re

    # Split into non‐empty lines
    lines = [line for line in timetable_str.splitlines() if line.strip()]
    if len(lines) < 3:
        return {}
    
    # The first header row: tokens[0] and tokens[1] are "Station" and "Name".
    header_tokens = lines[0].split()
    # Number of scheduled train columns is everything after the first 2 tokens.
    num_trains = len(header_tokens) - 2

    # Create a mapping from train id (as string) to its offset within the times part.
    # A token in header_tokens with index i (i>=2) gets offset = i-2.
    target_trains = {"703", "303", "509"}
    train_to_offset = {}
    for i, token in enumerate(header_tokens[2:], start=2):
        if token in target_trains:
            train_to_offset[token] = i - 2

    # To store the time string for each train id at Mountain View and San Francisco.
    mv_times = {}   # departure times at Mountain View
    sf_times = {}   # arrival times at San Francisco

    # Data rows begin at line index 2 (the second header line is typically at index1)
    for line in lines[2:]:
        tokens = line.split()
        # There should be at least (num_trains) time tokens at the end.
        if len(tokens) < num_trains:
            continue
        # The last num_trains tokens are the scheduled times.
        time_tokens = tokens[-num_trains:]
        # The preceding tokens (could be more than two tokens) are the zone and station name.
        # We assume the first token is the zone and the rest form the station name.
        station_name = " ".join(tokens[:-num_trains])
        # We are looking for the two stations.
        if station_name == "Mountain View":
            for tid, off in train_to_offset.items():
                mv_times[tid] = time_tokens[off]
        elif station_name == "San Francisco":
            for tid, off in train_to_offset.items():
                sf_times[tid] = time_tokens[off]

    # Function to convert a time string like "4:47am" into minutes since midnight.
    def parse_time(time_str):
        m = re.match(r"(\d+):(\d+)(am|pm)", time_str)
        if not m:
            return None
        hour = int(m.group(1))
        minute = int(m.group(2))
        period = m.group(3)
        if period == "am" and hour == 12:
            hour = 0
        elif period == "pm" and hour != 12:
            hour += 12
        return hour * 60 + minute

    results = {}
    # For each target train, compute difference between arrival at San Francisco and departure from Mountain View.
    for tid in target_trains:
        dep_str = mv_times.get(tid)
        arr_str = sf_times.get(tid)
        # If no time is available for one of the stops, return None for that train.
        if (dep_str is None) or (arr_str is None) or (dep_str == "--") or (arr_str == "--"):
            results[tid] = None
        else:
            dep_min = parse_time(dep_str)
            arr_min = parse_time(arr_str)
            if dep_min is None or arr_min is None:
                results[tid] = None
            else:
                travel = arr_min - dep_min
                # In case the arrival time is after midnight (i.e. travel negative), adjust by adding 24 hours.
                if travel < 0:
                    travel += 24 * 60
                results[tid] = travel
    return results

def mtv_to_sf(timetable_str: str) -> dict:
    """
    Given a timetable as a string, return a dictionary with the travel time in minutes 
    from Mountain View to San Francisco for trains 703, 303, and 509.
    
    The timetable string is expected to start with two header lines. The first header line 
    begins with "Station Name" followed by train numbers. In each data row, the final N tokens 
    correspond to N scheduled times (one per train, where N equals the number of train ids in the header),
    and the remaining tokens (after the zone number in the first position) make up the station name.
    
    If a station time is "--" (missing), then that train’s result is set to None.
    """
    import re

    # Split into non‐empty lines
    lines = [line for line in timetable_str.splitlines() if line.strip()]
    if len(lines) < 3:
        return {}
    
    # The first header row: tokens[0] and tokens[1] are "Station" and "Name".
    header_tokens = lines[0].split()
    # Number of scheduled train columns is everything after the first 2 tokens.
    num_trains = len(header_tokens) - 2

    # Create a mapping from train id (as string) to its offset within the times part.
    # A token in header_tokens with index i (i>=2) gets offset = i-2.
    target_trains = {"703", "303", "509"}
    train_to_offset = {}
    for i, token in enumerate(header_tokens[2:], start=2):
        if token in target_trains:
            train_to_offset[token] = i - 2

    # To store the time string for each train id at Mountain View and San Francisco.
    mv_times = {}   # departure times at Mountain View
    sf_times = {}   # arrival times at San Francisco

    # Data rows begin at line index 2 (the second header line is typically at index1)
    for line in lines[2:]:
        tokens = line.split()
        # There should be at least (num_trains) time tokens at the end.
        if len(tokens) < num_trains:
            continue
        # The last num_trains tokens are the scheduled times.
        time_tokens = tokens[-num_trains:]
        # The preceding tokens (could be more than two tokens) are the zone and station name.
        # We assume the first token is the zone and the rest form the station name.
        station_name = " ".join(tokens[:-num_trains])
        # We are looking for the two stations.
        if station_name == "Mountain View":
            for tid, off in train_to_offset.items():
                mv_times[tid] = time_tokens[off]
        elif station_name == "San Francisco":
            for tid, off in train_to_offset.items():
                sf_times[tid] = time_tokens[off]

    # Function to convert a time string like "4:47am" into minutes since midnight.
    def parse_time(time_str):
        m = re.match(r"(\d+):(\d+)(am|pm)", time_str)
        if not m:
            return None
        hour = int(m.group(1))
        minute = int(m.group(2))
        period = m.group(3)
        if period == "am" and hour == 12:
            hour = 0
        elif period == "pm" and hour != 12:
            hour += 12
        return hour * 60 + minute

    results = {}
    # For each target train, compute difference between arrival at San Francisco and departure from Mountain View.
    for tid in target_trains:
        dep_str = mv_times.get(tid)
        arr_str = sf_times.get(tid)
        # If no time is available for one of the stops, return None for that train.
        if (dep_str is None) or (arr_str is None) or (dep_str == "--") or (arr_str == "--"):
            results[tid] = None
        else:
            dep_min = parse_time(dep_str)
            arr_min = parse_time(arr_str)
            if dep_min is None or arr_min is None:
                results[tid] = None
            else:
                travel = arr_min - dep_min
                # In case the arrival time is after midnight (i.e. travel negative), adjust by adding 24 hours.
                if travel < 0:
                    travel += 24 * 60
                results[tid] = travel
    return results




answer = mtv_to_sf('\n Station Name 101 501 103 401 105 701 301 403 107 703 303 405 109 705 305 407 111 503 113 505 115 507 117 509 119 511 121 513 123 307 409 125 707 309 411 127 709 311 413 129 711 313 415 131 515 133 135 137 139 141 143 145\nZone Service Type L1 L5 L1 L4 L1 B7 L3 L4 L1 B7 L3 L4 L1 B7 L3 L4 L1 L5 L1 L5 L1 L5 L1 L5 L1 L5 L1 L5 L1 L3 L4 L1 B7 L3 L4 L1 B7 L3 L4 L1 B7 L3 L4 L1 L5 L1 L1 L1 L1 L1 L1 L1\n6 Gilroy -- -- -- -- -- -- -- 5:52am -- -- 6:29am 6:50am -- -- 7:29am -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --\n6 San Martin -- -- -- -- -- -- -- 6:01am -- -- 6:38am 6:59am -- -- 7:38am -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --\n6 Morgan Hill -- -- -- -- -- -- -- 6:07am -- -- 6:44am 7:05am -- -- 7:44am -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --\n5 Blossom Hill -- -- -- -- -- -- -- 6:22am -- -- 6:59am 7:20am -- -- 7:59am -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --\n5 Capitol -- -- -- -- -- -- -- 6:28am -- -- 7:05am 7:26am -- -- 8:05am -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --\n4 Tamien 4:20am 5:00am -- 5:36am -- -- 6:16am 6:35am -- -- 7:12am 7:33am 7:46am -- 8:12am -- 8:48am -- -- -- 10:46am -- -- -- 12:46pm -- -- -- 2:46pm -- -- -- -- -- -- 4:46pm -- -- -- 5:43pm -- -- -- 6:48pm -- 7:46pm -- 8:36pm -- 9:36pm -- 11:05pm\n4 San Jose Diridon 4:26am 5:07am 5:13am 5:42am 5:52am 5:57am 6:23am 6:42am 6:52am 6:57am 7:21am 7:40am 7:52am 7:57am 8:21am 8:42am 8:54am 9:41am 9:52am 10:41am 10:52am 11:41am 11:52am 12:41pm 12:52pm 1:41pm 1:52pm 2:41pm 2:52pm 3:20pm 3:42pm 3:52pm 3:57pm 4:21pm 4:42pm 4:52pm 4:57pm 5:21pm 5:42pm 5:52pm 5:57pm 6:21pm 6:42pm 6:54pm 7:41pm 7:52pm 8:11pm 8:43pm 9:12pm 9:43pm 10:30pm 11:12pm\n4 College Park -- -- -- -- -- -- -- -- -- -- -- 7:44am -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 3:24pm -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --\n4 Santa Clara 4:32am 5:13am 5:19am 5:48am 5:58am -- -- 6:48am 6:58am -- -- 7:48am 7:58am -- -- 8:48am 9:00am 9:47am 9:58am 10:47am 10:58am 11:47am 11:58am 12:47pm 12:58pm 1:47pm 1:58pm 2:47pm 2:58pm -- 3:48pm 3:58pm -- -- 4:48pm 4:58pm -- -- 5:48pm 5:58pm -- -- 6:48pm 7:00pm 7:47pm 7:58pm 8:17pm 8:49pm 9:18pm 9:49pm 10:36pm 11:18pm\n4 Lawrence 4:38am -- 5:25am -- 6:07am -- 6:33am -- 7:07am -- 7:31am -- 8:07am -- 8:31am -- 9:06am -- 10:04am -- 11:04am -- 12:04pm -- 1:04pm -- 2:04pm -- 3:04pm 3:31pm -- 4:07pm -- 4:31pm -- 5:07pm -- 5:31pm -- 6:07pm -- 6:31pm -- 7:06pm -- 8:04pm 8:23pm 8:55pm 9:24pm 9:55pm 10:42pm 11:24pm\n3 Sunnyvale 4:42am 5:21am 5:29am 5:56am 6:12am -- 6:37am 6:56am 7:12am -- 7:35am 7:56am 8:12am -- 8:35am 8:56am 9:10am 9:54am 10:08am 10:54am 11:08am 11:54am 12:08pm 12:54pm 1:08pm 1:54pm 2:08pm 2:54pm 3:08pm 3:36pm 3:56pm 4:12pm -- 4:35pm 4:56pm 5:12pm -- 5:35pm 5:56pm 6:12pm -- 6:35pm 6:56pm 7:10pm 7:54pm 8:08pm 8:27pm 8:59pm 9:28pm 9:59pm 10:46pm 11:28pm\n3 Mountain View 4:47am 5:25am 5:34am 6:01am 6:17am 6:11am 6:42am 7:01am 7:17am 7:11am 7:40am 8:01am 8:17am 8:11am 8:40am 9:01am 9:15am 9:59am 10:13am 10:59am 11:13am 11:59am 12:13pm 12:59pm 1:13pm 1:59pm 2:13pm 2:59pm 3:13pm 3:41pm 4:01pm 4:17pm 4:11pm 4:40pm 5:01pm 5:17pm 5:11pm 5:40pm 6:01pm 6:17pm 6:11pm 6:40pm 7:01pm 7:15pm 7:59pm 8:13pm 8:32pm 9:04pm 9:33pm 10:04pm 10:51pm 11:33pm\n3 San Antonio 4:51am -- 5:38am -- 6:20am -- 6:46am -- 7:20am -- 7:44am -- 8:20am -- 8:44am -- 9:19am -- 10:17am -- 11:17am -- 12:17pm -- 1:17pm -- 2:17pm -- 3:17pm 3:44pm -- 4:20pm -- 4:44pm -- 5:20pm -- 5:44pm -- 6:20pm -- 6:44pm -- 7:19pm -- 8:17pm 8:36pm 9:08pm 9:37pm 10:08pm 10:55pm 11:37pm\n3 California Avenue 4:55am -- 5:42am -- 6:25am -- 6:50am -- 7:25am -- 7:48am -- 8:25am -- 8:48am -- 9:23am -- 10:22am -- 11:22am -- 12:22pm -- 1:22pm -- 2:22pm -- 3:22pm 3:49pm -- 4:25pm -- 4:48pm -- 5:25pm -- 5:48pm -- 6:25pm -- 6:48pm -- 7:23pm -- 8:21pm 8:40pm 9:12pm 9:41pm 10:12pm 10:59pm 11:41pm\n3 Palo Alto 4:59am 5:33am 5:46am 6:08am 6:29am 6:19am 6:54am 7:09am 7:29am 7:19am 7:52am 8:09am 8:29am 8:19am 8:52am 9:09am 9:27am 10:07am 10:26am 11:07am 11:26am 12:07pm 12:26pm 1:07pm 1:26pm 2:07pm 2:26pm 3:07pm 3:26pm 3:53pm 4:09pm 4:29pm 4:19pm 4:52pm 5:09pm 5:29pm 5:19pm 5:52pm 6:09pm 6:29pm 6:19pm 6:52pm 7:09pm 7:27pm 8:07pm 8:25pm 8:44pm 9:17pm 9:45pm 10:17pm 11:03pm 11:46pm\n3 Menlo Park 5:02am 5:37am 5:50am -- 6:32am -- 6:58am -- 7:32am -- 7:56am -- 8:32am -- 8:56am -- 9:31am 10:10am 10:30am 11:10am 11:30am 12:10pm 12:30pm 1:10pm 1:30pm 2:10pm 2:30pm 3:10pm 3:30pm 3:56pm -- 4:32pm -- 4:56pm -- 5:32pm -- 5:56pm -- 6:32pm -- 6:56pm -- 7:30pm 8:10pm 8:28pm 8:47pm 9:20pm 9:49pm 10:20pm 11:07pm 11:50pm\n2 Redwood City 5:08am 5:42am 5:55am 6:15am 6:38am 6:26am 7:03am 7:15am 7:38am 7:26am 8:01am 8:15am 8:38am 8:26am 9:01am 9:15am 9:36am 10:16am 10:35am 11:16am 11:35am 12:16pm 12:35pm 1:16pm 1:35pm 2:16pm 2:35pm 3:16pm 3:35pm 4:02pm 4:15pm 4:38pm 4:26pm 5:01pm 5:15pm 5:38pm 5:26pm 6:01pm 6:15pm 6:38pm 6:26pm 7:01pm 7:15pm 7:36pm 8:16pm 8:34pm 8:53pm 9:27pm 9:55pm 10:27pm 11:13pm 11:56pm\n2 San Carlos 5:13am -- 6:00am 6:20am 6:42am -- -- 7:20am 7:42am -- -- 8:20am 8:42am -- -- 9:20am 9:41am -- 10:40am -- 11:40am -- 12:40pm -- 1:40pm -- 2:40pm -- 3:40pm -- 4:20pm 4:42pm -- -- 5:20pm 5:42pm -- -- 6:20pm 6:42pm -- -- 7:20pm 7:41pm -- 8:39pm 8:58pm 9:32pm 10:00pm 10:32pm 11:18pm 11:59pm\n2 Belmont 5:16am -- 6:04am -- 6:46am -- 7:09am -- 7:46am -- 8:07am -- 8:46am -- 9:07am -- 9:44am -- 10:43am -- 11:43am -- 12:43pm -- 1:43pm -- 2:43pm -- 3:43pm 4:08pm -- 4:46pm -- 5:07pm -- 5:46pm -- 6:07pm -- 6:46pm -- 7:07pm -- 7:44pm -- 8:42pm 9:01pm 9:35pm 10:04pm 10:35pm 11:22pm 12:05am\n2 Hillsdale 5:20am 5:50am 6:08am -- 6:50am 6:34am 7:13am -- 7:50am 7:34am 8:11am -- 8:50am 8:34am 9:11am -- 9:48am 10:23am 10:47am 11:23am 11:47am 12:23pm 12:47pm 1:23pm 1:47pm 2:23pm 2:47pm 3:23pm 3:47pm 4:12pm -- 4:50pm 4:34pm 5:11pm -- 5:50pm 5:34pm 6:11pm -- 6:50pm 6:34pm 7:11pm -- 7:49pm 8:24pm 8:47pm 9:06pm 9:39pm 10:08pm 10:39pm 11:26pm 12:09am\n2 Hayward Park 5:23am -- 6:11am -- 6:53am -- -- -- 7:53am -- -- -- 8:53am -- -- -- 9:51am -- 10:50am -- 11:50am -- 12:50pm -- 1:50pm -- 2:50pm -- 3:50pm -- -- 4:53pm -- -- -- 5:53pm -- -- -- 6:53pm -- -- -- 7:52pm -- 8:50pm 9:09pm 9:42pm 10:11pm 10:42pm 11:29pm 12:12am\n2 San Mateo 5:26am 5:55am 6:14am 6:28am 6:56am -- -- 7:28am 7:56am -- -- 8:28am 8:56am -- -- 9:28am 9:55am 10:29am 10:54am 11:29am 11:54am 12:29pm 12:54pm 1:29pm 1:54pm 2:29pm 2:54pm 3:29pm 3:54pm -- 4:28pm 4:56pm -- -- 5:28pm 5:56pm -- -- 6:28pm 6:56pm -- -- 7:28pm 7:56pm 8:29pm 8:54pm 9:13pm 9:46pm 10:15pm 10:46pm 11:33pm 12:16am\n2 Burlingame 5:30am -- 6:18am 6:31am 7:00am -- -- 7:31am 8:00am -- -- 8:31am 9:00am -- -- 9:31am 9:59am -- 10:58am -- 11:58am -- 12:58pm -- 1:58pm -- 2:58pm -- 3:58pm -- 4:31pm 5:00pm -- -- 5:31pm 6:00pm -- -- 6:31pm 7:00pm -- -- 7:31pm 8:00pm -- 8:58pm 9:17pm 9:50pm 10:18pm 10:50pm 11:36pm 12:19am\n2 Millbrae 5:35am 6:01am 6:23am 6:36am 7:04am 6:44am 7:21am 7:36am 8:04am 7:44am 8:19am 8:36am 9:04am 8:44am 9:19am 9:37am 10:04am 10:36am 11:03am 11:36am 12:03pm 12:36pm 1:03pm 1:36pm 2:03pm 2:36pm 3:03pm 3:36pm 4:03pm 4:20pm 4:36pm 5:04pm 4:44pm 5:19pm 5:36pm 6:04pm 5:44pm 6:19pm 6:36pm 7:04pm 6:44pm 7:19pm 7:36pm 8:06pm 8:35pm 9:04pm 9:23pm 9:55pm 10:24pm 10:55pm 11:42pm 12:26am\n1 San Bruno 5:39am -- 6:28am 6:41am 7:09am -- -- 7:41am 8:09am -- -- 8:41am 9:09am -- -- 9:42am 10:08am -- 11:08am -- 12:08pm -- 1:08pm -- 2:08pm -- 3:08pm -- 4:08pm -- 4:41pm 5:09pm -- -- 5:41pm 6:09pm -- -- 6:41pm 7:09pm -- -- 7:41pm 8:10pm -- 9:08pm 9:27pm 10:00pm 10:29pm 10:59pm 11:47pm 12:30am\n1 South San Francisco 5:43am -- 6:32am -- 7:13am -- 7:28am -- 8:13am -- 8:26am -- 9:13am -- 9:26am -- 10:13am -- 11:13am -- 12:13pm -- 1:13pm -- 2:13pm -- 3:13pm -- 4:13pm 4:27pm -- 5:13pm -- 5:26pm -- 6:13pm -- 6:26pm -- 7:13pm -- 7:26pm -- 8:14pm -- 9:12pm 9:31pm 10:04pm 10:33pm 11:03pm 11:51pm 12:34am\n1 Bayshore 5:50am -- 6:38am -- 7:19am -- -- -- 8:19am -- -- -- 9:19am -- -- -- 10:19am -- 11:19am -- 12:19pm -- 1:19pm -- 2:19pm -- 3:19pm -- 4:19pm -- -- 5:19pm -- -- -- 6:19pm -- -- -- 7:19pm -- -- -- 8:21pm -- 9:19pm 9:38pm 10:11pm 10:39pm 11:10pm 11:57pm 12:40am\n1 22nd Street 5:55am 6:14am 6:44am 6:52am 7:24am -- -- 7:52am 8:24am -- -- 8:52am 9:24am -- -- 9:53am 10:25am 10:49am 11:25am 11:49am 12:25pm 12:49pm 1:25pm 1:49pm 2:25pm 2:49pm 3:25pm 3:49pm 4:25pm 4:36pm 4:52pm 5:24pm 4:58pm 5:35pm 5:52pm 6:24pm 5:58pm 6:35pm 6:52pm 7:25pm 6:58pm 7:35pm 7:52pm 8:27pm 8:50pm 9:25pm 9:44pm 10:16pm 10:45pm 11:15pm 12:03am 12:46am\n1 San Francisco 6:01am 6:20am 6:50am 6:58am 7:31am 7:03am 7:41am 7:58am 8:31am 8:03am 8:39am 8:58am 9:31am 9:03am 9:39am 9:59am 10:31am 10:55am 11:31am 11:55am 12:31pm 12:55pm 1:31pm 1:55pm 2:31pm 2:55pm 3:31pm 3:55pm 4:31pm 4:41pm 4:58pm 5:31pm 5:03pm 5:41pm 5:58pm 6:31pm 6:03pm 6:41pm 6:58pm 7:32pm 7:03pm 7:41pm 7:58pm 8:33pm 8:59pm 9:31pm 9:50pm 10:24pm 10:53pm 11:23pm 12:11am 12:52am\n')
expected = {'703': 52, '303': 59, '509': 56}
assert answer == expected, f'Wrong answer; got {answer} instead of {expected}'
print('All tests passed')

#!/usr/bin/env python3
import re

def mtv_to_sf(timetable: str) -> dict:
    """
    Given a timetable as a string, returns a dictionary mapping each of the train IDs
    "703", "303", and "509" to the travel time (in minutes) from Mountain View to San Francisco.
    
    The timetable is expected to have two header rows. The first header row contains
    "Station Name" in its first column and then the train identifiers. The subsequent rows
    are for each station (their first column contains a line number and station name).
    """
    # Helper to convert time string (e.g. "4:47am") to minutes after midnight.
    def time_to_minutes(timestr: str) -> int:
        # Expect string like "4:47am" or "12:52pm". Raise error if format is unexpected.
        # Remove any leading/trailing spaces.
        timestr = timestr.strip().lower()
        # Use regex to parse hour:minute and am/pm.
        m = re.match(r'(\d{1,2}):(\d{2})(am|pm)', timestr)
        if not m:
            raise ValueError(f"Time format not recognized: {timestr}")
        hour, minute, ampm = m.groups()
        hour = int(hour)
        minute = int(minute)
        # Convert to 24-hour clock.
        if ampm == 'pm' and hour != 12:
            hour += 12
        elif ampm == 'am' and hour == 12:
            hour = 0
        return hour * 60 + minute

    # Split the timetable into lines and ignore empty lines.
    lines = [line for line in timetable.splitlines() if line.strip()]
    if len(lines) < 3:
        raise ValueError("Timetable does not have enough lines")
    
    # Use regex split on 2+ whitespace.
    header1 = re.split(r'\s{2,}', lines[0].strip())
    # header1[0] should be "Station Name", then the train IDs. For example:
    # ["Station Name", "101", "501", "103", ... , "703", "303", ... "509", ... ]
    
    # We are interested in these train numbers.
    target_trains = {"703", "303", "509"}
    # Build a mapping from train id to its column index (in the row list produced by re.split())
    train_to_index = {}
    for idx, token in enumerate(header1):
        if token in target_trains:
            train_to_index[token] = idx

    if len(train_to_index) != len(target_trains):
        missing = target_trains - set(train_to_index.keys())
        raise ValueError(f"Could not find train(s) {missing} in header")
    
    # Initialize variables to store the row data for departure (Mountain View)
    # and arrival (San Francisco)
    row_mtv = None
    row_sf = None

    # Starting from line 2 (index 2) because line 0 and line 1 are headers.
    for line in lines[2:]:
        tokens = re.split(r'\s{2,}', line.strip())
        if not tokens:
            continue
        # The station identifier is contained in the first token. (It might be e.g. "3 Mountain View")
        station_token = tokens[0]
        if "Mountain View" in station_token:
            row_mtv = tokens
        elif "San Francisco" in station_token:
            row_sf = tokens
        # If both found, break early.
        if row_mtv and row_sf:
            break

    if row_mtv is None:
        raise ValueError("No data row found for Mountain View")
    if row_sf is None:
        raise ValueError("No data row found for San Francisco")
    
    # For each target train, extract the Mountain View departure time and San Francisco arrival time.
    results = {}
    for train in target_trains:
        col = train_to_index[train]
        try:
            dep_str = row_mtv[col].strip()
            arr_str = row_sf[col].strip()
        except IndexError:
            raise ValueError(f"Column index {col} for train {train} missing in one of the rows")

        # Check that we have valid times (and not placeholders like "--")
        if dep_str == "--" or arr_str == "--":
            raise ValueError(f"Missing time for train {train} (dep: {dep_str}, arr: {arr_str})")
        
        # Convert times to minutes
        dep_minutes = time_to_minutes(dep_str)
        arr_minutes = time_to_minutes(arr_str)
        
        travel_time = arr_minutes - dep_minutes
        if travel_time < 0:
            # If the schedule passes midnight, adjust by adding 24 hours.
            travel_time += 24 * 60
        
        results[train] = travel_time

    return results

#!/usr/bin/env python3
import re

def mtv_to_sf(timetable: str) -> dict:
    """
    Given a timetable as a string, returns a dictionary mapping each of the train IDs
    "703", "303", and "509" to the travel time (in minutes) from Mountain View to San Francisco.
    
    The timetable is expected to have two header rows. The first header row contains
    "Station Name" in its first column and then the train identifiers. The subsequent rows
    are for each station (their first column contains a line number and station name).
    """
    # Helper to convert time string (e.g. "4:47am") to minutes after midnight.
    def time_to_minutes(timestr: str) -> int:
        # Expect string like "4:47am" or "12:52pm". Raise error if format is unexpected.
        # Remove any leading/trailing spaces.
        timestr = timestr.strip().lower()
        # Use regex to parse hour:minute and am/pm.
        m = re.match(r'(\d{1,2}):(\d{2})(am|pm)', timestr)
        if not m:
            raise ValueError(f"Time format not recognized: {timestr}")
        hour, minute, ampm = m.groups()
        hour = int(hour)
        minute = int(minute)
        # Convert to 24-hour clock.
        if ampm == 'pm' and hour != 12:
            hour += 12
        elif ampm == 'am' and hour == 12:
            hour = 0
        return hour * 60 + minute

    # Split the timetable into lines and ignore empty lines.
    lines = [line for line in timetable.splitlines() if line.strip()]
    if len(lines) < 3:
        raise ValueError("Timetable does not have enough lines")
    
    # Use regex split on 2+ whitespace.
    header1 = re.split(r'\s{2,}', lines[0].strip())
    # header1[0] should be "Station Name", then the train IDs. For example:
    # ["Station Name", "101", "501", "103", ... , "703", "303", ... "509", ... ]
    
    # We are interested in these train numbers.
    target_trains = {"703", "303", "509"}
    # Build a mapping from train id to its column index (in the row list produced by re.split())
    train_to_index = {}
    for idx, token in enumerate(header1):
        if token in target_trains:
            train_to_index[token] = idx

    if len(train_to_index) != len(target_trains):
        missing = target_trains - set(train_to_index.keys())
        raise ValueError(f"Could not find train(s) {missing} in header")
    
    # Initialize variables to store the row data for departure (Mountain View)
    # and arrival (San Francisco)
    row_mtv = None
    row_sf = None

    # Starting from line 2 (index 2) because line 0 and line 1 are headers.
    for line in lines[2:]:
        tokens = re.split(r'\s{2,}', line.strip())
        if not tokens:
            continue
        # The station identifier is contained in the first token. (It might be e.g. "3 Mountain View")
        station_token = tokens[0]
        if "Mountain View" in station_token:
            row_mtv = tokens
        elif "San Francisco" in station_token:
            row_sf = tokens
        # If both found, break early.
        if row_mtv and row_sf:
            break

    if row_mtv is None:
        raise ValueError("No data row found for Mountain View")
    if row_sf is None:
        raise ValueError("No data row found for San Francisco")
    
    # For each target train, extract the Mountain View departure time and San Francisco arrival time.
    results = {}
    for train in target_trains:
        col = train_to_index[train]
        try:
            dep_str = row_mtv[col].strip()
            arr_str = row_sf[col].strip()
        except IndexError:
            raise ValueError(f"Column index {col} for train {train} missing in one of the rows")

        # Check that we have valid times (and not placeholders like "--")
        if dep_str == "--" or arr_str == "--":
            raise ValueError(f"Missing time for train {train} (dep: {dep_str}, arr: {arr_str})")
        
        # Convert times to minutes
        dep_minutes = time_to_minutes(dep_str)
        arr_minutes = time_to_minutes(arr_str)
        
        travel_time = arr_minutes - dep_minutes
        if travel_time < 0:
            # If the schedule passes midnight, adjust by adding 24 hours.
            travel_time += 24 * 60
        
        results[train] = travel_time

    return results




answer = mtv_to_sf('\n Station Name 101 501 103 401 105 701 301 403 107 703 303 405 109 705 305 407 111 503 113 505 115 507 117 509 119 511 121 513 123 307 409 125 707 309 411 127 709 311 413 129 711 313 415 131 515 133 135 137 139 141 143 145\nZone Service Type L1 L5 L1 L4 L1 B7 L3 L4 L1 B7 L3 L4 L1 B7 L3 L4 L1 L5 L1 L5 L1 L5 L1 L5 L1 L5 L1 L5 L1 L3 L4 L1 B7 L3 L4 L1 B7 L3 L4 L1 B7 L3 L4 L1 L5 L1 L1 L1 L1 L1 L1 L1\n6 Gilroy -- -- -- -- -- -- -- 5:52am -- -- 6:29am 6:50am -- -- 7:29am -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --\n6 San Martin -- -- -- -- -- -- -- 6:01am -- -- 6:38am 6:59am -- -- 7:38am -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --\n6 Morgan Hill -- -- -- -- -- -- -- 6:07am -- -- 6:44am 7:05am -- -- 7:44am -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --\n5 Blossom Hill -- -- -- -- -- -- -- 6:22am -- -- 6:59am 7:20am -- -- 7:59am -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --\n5 Capitol -- -- -- -- -- -- -- 6:28am -- -- 7:05am 7:26am -- -- 8:05am -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --\n4 Tamien 4:20am 5:00am -- 5:36am -- -- 6:16am 6:35am -- -- 7:12am 7:33am 7:46am -- 8:12am -- 8:48am -- -- -- 10:46am -- -- -- 12:46pm -- -- -- 2:46pm -- -- -- -- -- -- 4:46pm -- -- -- 5:43pm -- -- -- 6:48pm -- 7:46pm -- 8:36pm -- 9:36pm -- 11:05pm\n4 San Jose Diridon 4:26am 5:07am 5:13am 5:42am 5:52am 5:57am 6:23am 6:42am 6:52am 6:57am 7:21am 7:40am 7:52am 7:57am 8:21am 8:42am 8:54am 9:41am 9:52am 10:41am 10:52am 11:41am 11:52am 12:41pm 12:52pm 1:41pm 1:52pm 2:41pm 2:52pm 3:20pm 3:42pm 3:52pm 3:57pm 4:21pm 4:42pm 4:52pm 4:57pm 5:21pm 5:42pm 5:52pm 5:57pm 6:21pm 6:42pm 6:54pm 7:41pm 7:52pm 8:11pm 8:43pm 9:12pm 9:43pm 10:30pm 11:12pm\n4 College Park -- -- -- -- -- -- -- -- -- -- -- 7:44am -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 3:24pm -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --\n4 Santa Clara 4:32am 5:13am 5:19am 5:48am 5:58am -- -- 6:48am 6:58am -- -- 7:48am 7:58am -- -- 8:48am 9:00am 9:47am 9:58am 10:47am 10:58am 11:47am 11:58am 12:47pm 12:58pm 1:47pm 1:58pm 2:47pm 2:58pm -- 3:48pm 3:58pm -- -- 4:48pm 4:58pm -- -- 5:48pm 5:58pm -- -- 6:48pm 7:00pm 7:47pm 7:58pm 8:17pm 8:49pm 9:18pm 9:49pm 10:36pm 11:18pm\n4 Lawrence 4:38am -- 5:25am -- 6:07am -- 6:33am -- 7:07am -- 7:31am -- 8:07am -- 8:31am -- 9:06am -- 10:04am -- 11:04am -- 12:04pm -- 1:04pm -- 2:04pm -- 3:04pm 3:31pm -- 4:07pm -- 4:31pm -- 5:07pm -- 5:31pm -- 6:07pm -- 6:31pm -- 7:06pm -- 8:04pm 8:23pm 8:55pm 9:24pm 9:55pm 10:42pm 11:24pm\n3 Sunnyvale 4:42am 5:21am 5:29am 5:56am 6:12am -- 6:37am 6:56am 7:12am -- 7:35am 7:56am 8:12am -- 8:35am 8:56am 9:10am 9:54am 10:08am 10:54am 11:08am 11:54am 12:08pm 12:54pm 1:08pm 1:54pm 2:08pm 2:54pm 3:08pm 3:36pm 3:56pm 4:12pm -- 4:35pm 4:56pm 5:12pm -- 5:35pm 5:56pm 6:12pm -- 6:35pm 6:56pm 7:10pm 7:54pm 8:08pm 8:27pm 8:59pm 9:28pm 9:59pm 10:46pm 11:28pm\n3 Mountain View 4:47am 5:25am 5:34am 6:01am 6:17am 6:11am 6:42am 7:01am 7:17am 7:11am 7:40am 8:01am 8:17am 8:11am 8:40am 9:01am 9:15am 9:59am 10:13am 10:59am 11:13am 11:59am 12:13pm 12:59pm 1:13pm 1:59pm 2:13pm 2:59pm 3:13pm 3:41pm 4:01pm 4:17pm 4:11pm 4:40pm 5:01pm 5:17pm 5:11pm 5:40pm 6:01pm 6:17pm 6:11pm 6:40pm 7:01pm 7:15pm 7:59pm 8:13pm 8:32pm 9:04pm 9:33pm 10:04pm 10:51pm 11:33pm\n3 San Antonio 4:51am -- 5:38am -- 6:20am -- 6:46am -- 7:20am -- 7:44am -- 8:20am -- 8:44am -- 9:19am -- 10:17am -- 11:17am -- 12:17pm -- 1:17pm -- 2:17pm -- 3:17pm 3:44pm -- 4:20pm -- 4:44pm -- 5:20pm -- 5:44pm -- 6:20pm -- 6:44pm -- 7:19pm -- 8:17pm 8:36pm 9:08pm 9:37pm 10:08pm 10:55pm 11:37pm\n3 California Avenue 4:55am -- 5:42am -- 6:25am -- 6:50am -- 7:25am -- 7:48am -- 8:25am -- 8:48am -- 9:23am -- 10:22am -- 11:22am -- 12:22pm -- 1:22pm -- 2:22pm -- 3:22pm 3:49pm -- 4:25pm -- 4:48pm -- 5:25pm -- 5:48pm -- 6:25pm -- 6:48pm -- 7:23pm -- 8:21pm 8:40pm 9:12pm 9:41pm 10:12pm 10:59pm 11:41pm\n3 Palo Alto 4:59am 5:33am 5:46am 6:08am 6:29am 6:19am 6:54am 7:09am 7:29am 7:19am 7:52am 8:09am 8:29am 8:19am 8:52am 9:09am 9:27am 10:07am 10:26am 11:07am 11:26am 12:07pm 12:26pm 1:07pm 1:26pm 2:07pm 2:26pm 3:07pm 3:26pm 3:53pm 4:09pm 4:29pm 4:19pm 4:52pm 5:09pm 5:29pm 5:19pm 5:52pm 6:09pm 6:29pm 6:19pm 6:52pm 7:09pm 7:27pm 8:07pm 8:25pm 8:44pm 9:17pm 9:45pm 10:17pm 11:03pm 11:46pm\n3 Menlo Park 5:02am 5:37am 5:50am -- 6:32am -- 6:58am -- 7:32am -- 7:56am -- 8:32am -- 8:56am -- 9:31am 10:10am 10:30am 11:10am 11:30am 12:10pm 12:30pm 1:10pm 1:30pm 2:10pm 2:30pm 3:10pm 3:30pm 3:56pm -- 4:32pm -- 4:56pm -- 5:32pm -- 5:56pm -- 6:32pm -- 6:56pm -- 7:30pm 8:10pm 8:28pm 8:47pm 9:20pm 9:49pm 10:20pm 11:07pm 11:50pm\n2 Redwood City 5:08am 5:42am 5:55am 6:15am 6:38am 6:26am 7:03am 7:15am 7:38am 7:26am 8:01am 8:15am 8:38am 8:26am 9:01am 9:15am 9:36am 10:16am 10:35am 11:16am 11:35am 12:16pm 12:35pm 1:16pm 1:35pm 2:16pm 2:35pm 3:16pm 3:35pm 4:02pm 4:15pm 4:38pm 4:26pm 5:01pm 5:15pm 5:38pm 5:26pm 6:01pm 6:15pm 6:38pm 6:26pm 7:01pm 7:15pm 7:36pm 8:16pm 8:34pm 8:53pm 9:27pm 9:55pm 10:27pm 11:13pm 11:56pm\n2 San Carlos 5:13am -- 6:00am 6:20am 6:42am -- -- 7:20am 7:42am -- -- 8:20am 8:42am -- -- 9:20am 9:41am -- 10:40am -- 11:40am -- 12:40pm -- 1:40pm -- 2:40pm -- 3:40pm -- 4:20pm 4:42pm -- -- 5:20pm 5:42pm -- -- 6:20pm 6:42pm -- -- 7:20pm 7:41pm -- 8:39pm 8:58pm 9:32pm 10:00pm 10:32pm 11:18pm 11:59pm\n2 Belmont 5:16am -- 6:04am -- 6:46am -- 7:09am -- 7:46am -- 8:07am -- 8:46am -- 9:07am -- 9:44am -- 10:43am -- 11:43am -- 12:43pm -- 1:43pm -- 2:43pm -- 3:43pm 4:08pm -- 4:46pm -- 5:07pm -- 5:46pm -- 6:07pm -- 6:46pm -- 7:07pm -- 7:44pm -- 8:42pm 9:01pm 9:35pm 10:04pm 10:35pm 11:22pm 12:05am\n2 Hillsdale 5:20am 5:50am 6:08am -- 6:50am 6:34am 7:13am -- 7:50am 7:34am 8:11am -- 8:50am 8:34am 9:11am -- 9:48am 10:23am 10:47am 11:23am 11:47am 12:23pm 12:47pm 1:23pm 1:47pm 2:23pm 2:47pm 3:23pm 3:47pm 4:12pm -- 4:50pm 4:34pm 5:11pm -- 5:50pm 5:34pm 6:11pm -- 6:50pm 6:34pm 7:11pm -- 7:49pm 8:24pm 8:47pm 9:06pm 9:39pm 10:08pm 10:39pm 11:26pm 12:09am\n2 Hayward Park 5:23am -- 6:11am -- 6:53am -- -- -- 7:53am -- -- -- 8:53am -- -- -- 9:51am -- 10:50am -- 11:50am -- 12:50pm -- 1:50pm -- 2:50pm -- 3:50pm -- -- 4:53pm -- -- -- 5:53pm -- -- -- 6:53pm -- -- -- 7:52pm -- 8:50pm 9:09pm 9:42pm 10:11pm 10:42pm 11:29pm 12:12am\n2 San Mateo 5:26am 5:55am 6:14am 6:28am 6:56am -- -- 7:28am 7:56am -- -- 8:28am 8:56am -- -- 9:28am 9:55am 10:29am 10:54am 11:29am 11:54am 12:29pm 12:54pm 1:29pm 1:54pm 2:29pm 2:54pm 3:29pm 3:54pm -- 4:28pm 4:56pm -- -- 5:28pm 5:56pm -- -- 6:28pm 6:56pm -- -- 7:28pm 7:56pm 8:29pm 8:54pm 9:13pm 9:46pm 10:15pm 10:46pm 11:33pm 12:16am\n2 Burlingame 5:30am -- 6:18am 6:31am 7:00am -- -- 7:31am 8:00am -- -- 8:31am 9:00am -- -- 9:31am 9:59am -- 10:58am -- 11:58am -- 12:58pm -- 1:58pm -- 2:58pm -- 3:58pm -- 4:31pm 5:00pm -- -- 5:31pm 6:00pm -- -- 6:31pm 7:00pm -- -- 7:31pm 8:00pm -- 8:58pm 9:17pm 9:50pm 10:18pm 10:50pm 11:36pm 12:19am\n2 Millbrae 5:35am 6:01am 6:23am 6:36am 7:04am 6:44am 7:21am 7:36am 8:04am 7:44am 8:19am 8:36am 9:04am 8:44am 9:19am 9:37am 10:04am 10:36am 11:03am 11:36am 12:03pm 12:36pm 1:03pm 1:36pm 2:03pm 2:36pm 3:03pm 3:36pm 4:03pm 4:20pm 4:36pm 5:04pm 4:44pm 5:19pm 5:36pm 6:04pm 5:44pm 6:19pm 6:36pm 7:04pm 6:44pm 7:19pm 7:36pm 8:06pm 8:35pm 9:04pm 9:23pm 9:55pm 10:24pm 10:55pm 11:42pm 12:26am\n1 San Bruno 5:39am -- 6:28am 6:41am 7:09am -- -- 7:41am 8:09am -- -- 8:41am 9:09am -- -- 9:42am 10:08am -- 11:08am -- 12:08pm -- 1:08pm -- 2:08pm -- 3:08pm -- 4:08pm -- 4:41pm 5:09pm -- -- 5:41pm 6:09pm -- -- 6:41pm 7:09pm -- -- 7:41pm 8:10pm -- 9:08pm 9:27pm 10:00pm 10:29pm 10:59pm 11:47pm 12:30am\n1 South San Francisco 5:43am -- 6:32am -- 7:13am -- 7:28am -- 8:13am -- 8:26am -- 9:13am -- 9:26am -- 10:13am -- 11:13am -- 12:13pm -- 1:13pm -- 2:13pm -- 3:13pm -- 4:13pm 4:27pm -- 5:13pm -- 5:26pm -- 6:13pm -- 6:26pm -- 7:13pm -- 7:26pm -- 8:14pm -- 9:12pm 9:31pm 10:04pm 10:33pm 11:03pm 11:51pm 12:34am\n1 Bayshore 5:50am -- 6:38am -- 7:19am -- -- -- 8:19am -- -- -- 9:19am -- -- -- 10:19am -- 11:19am -- 12:19pm -- 1:19pm -- 2:19pm -- 3:19pm -- 4:19pm -- -- 5:19pm -- -- -- 6:19pm -- -- -- 7:19pm -- -- -- 8:21pm -- 9:19pm 9:38pm 10:11pm 10:39pm 11:10pm 11:57pm 12:40am\n1 22nd Street 5:55am 6:14am 6:44am 6:52am 7:24am -- -- 7:52am 8:24am -- -- 8:52am 9:24am -- -- 9:53am 10:25am 10:49am 11:25am 11:49am 12:25pm 12:49pm 1:25pm 1:49pm 2:25pm 2:49pm 3:25pm 3:49pm 4:25pm 4:36pm 4:52pm 5:24pm 4:58pm 5:35pm 5:52pm 6:24pm 5:58pm 6:35pm 6:52pm 7:25pm 6:58pm 7:35pm 7:52pm 8:27pm 8:50pm 9:25pm 9:44pm 10:16pm 10:45pm 11:15pm 12:03am 12:46am\n1 San Francisco 6:01am 6:20am 6:50am 6:58am 7:31am 7:03am 7:41am 7:58am 8:31am 8:03am 8:39am 8:58am 9:31am 9:03am 9:39am 9:59am 10:31am 10:55am 11:31am 11:55am 12:31pm 12:55pm 1:31pm 1:55pm 2:31pm 2:55pm 3:31pm 3:55pm 4:31pm 4:41pm 4:58pm 5:31pm 5:03pm 5:41pm 5:58pm 6:31pm 6:03pm 6:41pm 6:58pm 7:32pm 7:03pm 7:41pm 7:58pm 8:33pm 8:59pm 9:31pm 9:50pm 10:24pm 10:53pm 11:23pm 12:11am 12:52am\n')
expected = {'703': 52, '303': 59, '509': 56}
assert answer == expected, f'Wrong answer; got {answer} instead of {expected}'
print('All tests passed')