def can_hike_to(elevation_map: List[List[int]], start: List[int],
                dest: List[int], supplies: int) -> bool:
    '''Return True if and only if a hiker can move from start to dest in
    elevation_map without running out of supplies.

    Precondition: elevation_map is a valid elevation map.
                  start and dest are valid cells in elevation_map.
                  dest is North-West of start.
                  supplies >= 0

    >>> map = [[1, 6, 5, 6],
    ...        [2, 5, 6, 8],
    ...        [7, 2, 8, 1],
    ...        [4, 4, 7, 3]]
    >>> can_hike_to(map, [3, 3], [2, 2], 10)
    True
    >>> can_hike_to(map, [3, 3], [2, 2], 8)
    False
    >>> can_hike_to(map, [3, 3], [3, 0], 7)
    True
    >>> can_hike_to(map, [3, 3], [3, 0], 6)
    False
    >>> can_hike_to(map, [3, 3], [0, 0], 18)
    True
    >>> can_hike_to(map, [3, 3], [0, 0], 17)
    False
    '''
    change_west = (elevation_map[start[0]][start[1]])-(elevation_map[start[0]][start[1]-1])
    change_north = (elevation_map[start[0]][start[1]])-(elevation_map[start[0]-1][start[1]])

    while start[0][1] != dest[0][1]:
        if start[0] == dest[0]:
            elevation_map[start[0]][start[1]-1]
            change = elevation_map[start[0]][start[1]] - elevation_map[start[0]][start[1]-1]
            supplies = supplies - abs(change)

        elif start[1] == dest[1]:
            elevation_map[start[0]-1][start[1]]
            change = elevation_map[start[0]][start[1]] - elevation_map[start[0]-1][start[0]]
            supplies = supplies - abs(change)
        elif change_west < change_north:
            elevation_map[start[0]][start[1]-1]
            change = elevation_map[start[0]][start[1]] - elevation_map[start[0]][start[1]-1]
            supplies = supplies - abs(change)

        elif change_north < change_west:
            elevation_map[start[0]-1][start[1]]
            supplies = supplies - abs(change_north)
        elif change_west < change_north:
            elevation_map[start[0]][start[1]-1]
            supplies = supplies - abs(change_west)
        if supplies < 0:
            return False
    return True