human
I found an interesting problem on https://codeforces.com/problemset/problem/585/B:
The mobile application store has a new game called "Subway Roller".

The protagonist of the game Philip is located in one end of the tunnel and wants to get out of the other one. The tunnel is a rectangular field consisting of three rows and n columns. At the beginning of the game the hero is in some cell of the leftmost column. Some number of trains rides towards the hero. Each train consists of two or more neighbouring cells in some row of the field.

All trains are moving from right to left at a speed of two cells per second, and the hero runs from left to right at the speed of one cell per second. For simplicity, the game is implemented so that the hero and the trains move in turns. First, the hero moves one cell to the right, then one square up or down, or stays idle. Then all the trains move twice simultaneously one cell to the left. Thus, in one move, Philip definitely makes a move to the right and can move up or down. If at any point, Philip is in the same cell with a train, he loses. If the train reaches the left column, it continues to move as before, leaving the tunnel.

Your task is to answer the question whether there is a sequence of movements of Philip, such that he would be able to get to the rightmost column.

 [Image] 

-----Input-----

Each test contains from one to ten sets of the input data. The first line of the test contains a single integer t (1 ≤ t ≤ 10 for pretests and tests or t = 1 for hacks.
see the Notes section for details) — the number of sets.

Then follows the description of t sets of the input data. 

The first line of the description of each set contains two integers n, k (2 ≤ n ≤ 100, 1 ≤ k ≤ 26) — the number of columns on the field and the number of trains. Each of the following three lines contains the sequence of n character, representing the row of the field where the game is on. Philip's initial position is marked as 's', he is in the leftmost column. Each of the k trains is marked by some sequence of identical uppercase letters of the English alphabet, located in...

I tried it in Python, but could not do it. Can you solve it?

Write me a the Python program you requested?
assistant
#Here is the Python program you requested.

from queue import Queue
from collections import defaultdict

class PhilipTrains():
    def __init__(self, n, k, state):
        self.n = n
        self.k = k
        self.state = state
        self.graph = [[[0 for i in range(n+1)] for j in range(n)] for k in range(3)]
        for i in range(len(state)):
            for j in range(len(state[i])):
                if 'A' <= state[i][j] <= 'Z':
                    for k in range(n):
                        nj = j-(2*k)
                        if nj >= 0:
                            self.graph[i][nj][k] = -1
                        else:
                            break
        for i in range(len(state)):
            if state[i][0] == 's':
                self.r = i
                self.c = 0

    def check_reach(self):
        q = Queue()
        check = defaultdict(int)

        changes = [(1,1,1),(-1,1,1), (0,1,1)]

        q.put((self.r, self.c, 0))
        check[(self.r, self.c, 0)] = 1

        while not q.empty():
            pr, pc, pt = q.get()
            if self.graph[pr][pc][pt] == -1:
                continue
            if pc == self.n-1:
                return 'YES'
            if self.graph[pr][pc+1][pt] != -1:
                if check[(pr, pc+1,pt+1)] != 1:
                    q.put((pr, pc+1,pt+1))
                    check[(pr, pc+1, pt+1)] = 1
                for ch in [1,-1]:
                    if 0 <= pr+ch <= 2 and check[(pr+ch, pc+1,pt+1)] != 1 and self.graph[pr+ch][pc+1][pt] != -1:
                        q.put((pr+ch, pc+1,pt+1))
                        check[(pr+ch, pc+1, pt+1)] = 1
        return 'NO'

t = int(input())

for i in range(t):
    n, k = list(map(int,input().strip(' ').split(' ')))
    arr = []
    for i in range(3):
        arr.append(input().strip(' '))
    graph = PhilipTrains(n, k, arr)
    print(graph.check_reach())