【HDOJ】3592 World Exhibition

基础差分约束。

 /* 3592 */
 #include <iostream>
 #include <algorithm>
 #include <queue>
 #include <vector>
 #include <cstdio>
 #include <cstring>
 using namespace std;

 #define MAXN 1005
 #define MAXE 20005
 #define INF     0x3f3f3f3f

 typedef struct {
     int v, w, next;
 } Edge_t;

 Edge_t E[MAXE];
 int head[MAXN], L;
 int dis[MAXN], deg[MAXN];
 bool visit[MAXN];
 int n, x, y;

 void addEdge(int u, int v, int w) {
     E[L].v = v;
     E[L].w = w;
     E[L].next = head[u];
     head[u] = L++;
 }

 void init() {
     memset(head, -, sizeof(int)*(n+));
     memset(dis, 0x3f, sizeof(int)*(n+));
     memset(deg, , sizeof(int)*(n+));
     memset(visit, false, sizeof(bool)*(n+));
     L = ;
 }

 int spfa() {
     int i, j, k;
     int u, v, w;
     queue<int> Q;

     deg[] = ;
     visit[] = true;
     dis[] = ;
     Q.push();

     while (!Q.empty()) {
         u = Q.front();
         Q.pop();
         visit[u] = false;
         for (i=head[u]; i!=-; i=E[i].next) {
             v = E[i].v;
             w = E[i].w;
             if (dis[v] > dis[u] + w) {
                 dis[v] = dis[u] + w;
                 if (!visit[v]) {
                     visit[v] = true;
                     Q.push(v);
                     if (++deg[v] > n)
                         return -;
                 }
             }
         }
     }
     if (dis[n] == INF)
         return -;
     else
         return dis[n];
 }

 int main() {
     int t;
     int i, j, k;

     #ifndef ONLINE_JUDGE
         freopen("data.in", "r", stdin);
         freopen("data.out", "w", stdout);
     #endif

     scanf("%d", &t);
     while (t--) {
         scanf("%d %d %d", &n, &x, &y);
         init();
         while (x--) {
             scanf("%d %d %d", &i, &j, &k);
             addEdge(i, j, k);
         }
         while (y--) {
             scanf("%d %d %d", &i, &j, &k);
             addEdge(j, i, -k);
         }
         k = spfa();
         printf("%d\n", k);
     }

     return ;
 }