Holy Grail Bellman-Ford/spfa

Holy Grail

Bellman-Ford

 #include <bits/stdc++.h>
 using namespace std;
 const int maxn = , maxm = ;
 const int inf = 0x3f3f3f3f;
 struct edge {
     int v, w;
 };
 vector<edge> maps[maxn];
 int dis[maxn], n, m;

 bool BellmanFord(int s) {  // s为源点
     fill(dis, dis+n, inf);
     dis[s] = ;
     for (int i = ; i < n-; i++) {
         for (int u = ; u < n; u++) {
             for (int j = ; j < maps[u].size(); j++) {
                 int v = maps[u][j].v;
                 int w = maps[u][j].w;
                 if (dis[u] + w < dis[v]) {
                     dis[v] = dis[u] + w;
                 }
             }
         }
     }
     for (int u = ; u < n; u++) {
         for (int j = ; j < maps[u].size(); j++) {
             int v = maps[u][j].v;
             int w = maps[u][j].w;
             if (dis[u] + w < dis[v])
                 return false;
         }
     }
     return true;
 }
 int main() {
     int t; scanf("%d",&t);
     while (t--) {
         scanf("%d%d",&n,&m);
         for (int i = ; i < n; i++) maps[i].clear();

         for (int i = ; i <= m; i++) {
             int u, v, w; scanf("%d%d%d",&u,&v,&w);
             maps[u].push_back(edge{v,w});
         }
         for (int i = ; i <= ; i++) {
             int u, v; scanf("%d%d",&u,&v);
             bool flag = BellmanFord(v);
             printf("%d\n",-dis[u]);

             //if (flag == false) continue;
             maps[u].push_back(edge{v,-dis[u]});
         }
     }
 }

spfa

 #include<bits/stdc++.h>
 using namespace std;
 const int maxn = , maxm = ;
 struct edge {
     int v, w;
 };
 vector<edge> maps[maxn];
 int dis[maxn], n, m;
 bool vis[maxn];

 void add(int u, int v, int w) {
     maps[u].push_back(edge{v,w});
 }
 void spfa(int s) {
     memset(dis, 0x3f3f3f3f, sizeof(dis));
     memset(vis,,sizeof(vis));
     queue<int> que;
     que.push(s), dis[s] = , vis[s] = true;
     while(!que.empty()) {
         int u = que.front();
         que.pop();
         vis[u] = false;
         for(int i = ; i < maps[u].size(); i++) {
             int v = maps[u][i].v;
             int w = maps[u][i].w;
             if(dis[v] > dis[u]+w) {
                 dis[v] = dis[u] + w;
                 if(vis[v] == false) {
                     que.push(v);
                     vis[v] = true;
                 }
             }
         }
     }
 }
 int main() {
     int t; scanf("%d",&t);
     while(t--) {
         scanf("%d%d",&n,&m);
         for (int i = ; i < n; i++) maps[i].clear();
         for(int i = ; i <= m; i++) {
             int u, v, w; scanf("%d%d%d",&u,&v,&w);
             add(u,v,w);
         }
         for(int i = ; i <= ; i++) {
             int u, v; scanf("%d%d",&u,&v);
             spfa(v);
             add(u,v,-dis[u]);
             printf("%d\n",-dis[u]);
         }
     }
     return ;
 }