水题 最长路
1 #include <iostream> 2 #include<cstdio> 3 #include<cstring> 4 #include<algorithm> 5 #include<stdlib.h> 6 #include<queue> 7 #include<vector> 8 using namespace std; 9 int n,m; 10 vector<int>ed[510]; 11 int vis[510],dis[510],w[510][510]; 12 void spfa(int s,int e) 13 { 14 int i; 15 queue<int>q; 16 q.push(s); 17 vis[s] = 1; 18 while(!q.empty()) 19 { 20 int u = q.front(); 21 q.pop(); 22 vis[u] = 0; 23 for(i = 0 ; i < (int)ed[u].size() ; i++) 24 { 25 int v = ed[u][i]; 26 if(dis[v]<dis[u]+w[u][v]) 27 { 28 dis[v] = dis[u]+w[u][v]; 29 if(!vis[v]) 30 { 31 vis[v] = 1; 32 q.push(v); 33 } 34 } 35 } 36 } 37 if(dis[e]) 38 printf("%d ",dis[e]); 39 else 40 printf("No solution "); 41 } 42 int main() 43 { 44 int i; 45 scanf("%d%d",&n,&m); 46 for(i = 1; i <= m; i++) 47 { 48 int u,v,c; 49 scanf("%d%d%d",&u,&v,&c); 50 w[u][v] = c; 51 ed[u].push_back(v); 52 } 53 int s,e; 54 scanf("%d%d",&s,&e); 55 spfa(s,e); 56 return 0; 57 }