本文共 1185 字，大约阅读时间需要 3 分钟。

????????????????1????n????????????????????????BFS???????BFS??????????????

????

????

#include 
   
    #include 
    
     #include 
     
      using namespace std;int main() {    int k; // ??????    cin >> k;    for (int test = 0; test < k; ++test) {        int n, m;        cin >> n >> m;        vector
      
       
        > graph(n + 1);        vector
        
          distance(n + 1, -1); queue
         
           q; distance[1] = 0; q.push(1); bool found = false; while (!q.empty()) { int u = q.front(); q.pop(); for (int v : graph[u]) { if (distance[v] == -1) { distance[v] = distance[u] + 1; if (v == n) { found = true; break; } q.push(v); } } if (found) break; } if (distance[n] == -1) { cout << "NO" << endl; } else { cout << distance[n] << endl; } } return 0;}
         
        
       
      
     
    
   

????

??????????????????????????????

转载地址：http://pkexz.baihongyu.com/