HDU 5695 Gym Class 拓扑排序

题目链接：

http://acm.hdu.edu.cn/showproblem.php?pid=5695

题解：

求出字典序最大的拓扑序。然后把求好的数列翻转过来就是满足条件的数列，然后模拟求一下value就可以了。

 #include<iostream>
 #include<cstdio>
 #include<cstring>
 #include<queue>
 #include<vector>
 using namespace std;

 const int maxn = 1e5 + ;
 typedef long long LL;

 struct Edge {
     int v, ne;
     Edge(int v, int ne) :v(v), ne(ne) {}
     Edge() {}
 }egs[maxn*];

 int n, m;
 int head[maxn], ind[maxn],tot;

 void addEdge(int u, int v) {
     egs[tot] = Edge(v, head[u]);
     head[u] = tot++;
 }

 void init() {
     tot = ;
     memset(ind, , sizeof(ind));
     memset(head, -, sizeof(head));
 }

 int main() {
     int tc;
     scanf("%d", &tc);
     while (tc--) {
         init();
         scanf("%d%d", &n, &m);
         for (int i = ; i < m; i++) {
             int u, v;
             scanf("%d%d", &u, &v);
             addEdge(u, v);
             ind[v]++;
         }
         priority_queue<int> pq;
         for (int i = ; i <= n; i++) {
             if (ind[i] == ) pq.push(i);
         }
         vector<int> ans;
         while (!pq.empty()) {
             int u = pq.top(); pq.pop();
             ans.push_back(u);
             int p = head[u];
             while (p != -) {
                 Edge& e = egs[p];
                 ind[e.v]--;
                 if (ind[e.v] == ) {
                     pq.push(e.v);
                 }
                 p = e.ne;
             }
         }
         LL sum = ans[]; int mi = ans[];
         for (int i = ; i < ans.size(); i++) {
             mi = min(mi, ans[i]);
             sum += mi;
         }
         printf("%lld\n", sum);
     }
     return ;
 }