<filename>Algorithm-on-Graphs/10_paths_in_graphs_starter_files_1/bfs/bfs.py
#Uses python3

import sys
import queue
def distance(adj, s, t):
    visited=[False]*(len(adj))
    dist=[-1]*(len(adj))
    dist[s]=0
    queue=[]
    queue.append(s)

    while queue:
        s=queue.pop(0)
        for v in adj[s]:
            if visited[v]==False:
                visited[v]=True
                queue.append(v)
                dist[v]=dist[s]+1

    return dist[t]

if __name__ == '__main__':
    input = sys.stdin.read()
    data = list(map(int, input.split()))
    n, m = data[0:2]
    data = data[2:]
    edges = list(zip(data[0:(2 * m):2], data[1:(2 * m):2]))
    adj = [[] for _ in range(n)]
    for (a, b) in edges:
        adj[a - 1].append(b - 1)
        adj[b - 1].append(a - 1)
    s, t = data[2 * m] - 1, data[2 * m + 1] - 1
    print(distance(adj, s, t))

<filename>Algorithm-on-Graphs/10_paths_in_graphs_starter_files_1/bfs/bfs.py
#Uses python3

import sys
import queue
def distance(adj, s, t):
    visited=[False]*(len(adj))
    dist=[-1]*(len(adj))
    dist[s]=0
    queue=[]
    queue.append(s)

    while queue:
        s=queue.pop(0)
        for v in adj[s]:
            if visited[v]==False:
                visited[v]=True
                queue.append(v)
                dist[v]=dist[s]+1

    return dist[t]

if __name__ == '__main__':
    input = sys.stdin.read()
    data = list(map(int, input.split()))
    n, m = data[0:2]
    data = data[2:]
    edges = list(zip(data[0:(2 * m):2], data[1:(2 * m):2]))
    adj = [[] for _ in range(n)]
    for (a, b) in edges:
        adj[a - 1].append(b - 1)
        adj[b - 1].append(a - 1)
    s, t = data[2 * m] - 1, data[2 * m + 1] - 1
    print(distance(adj, s, t))

#Uses python3