A_star poj2449 k短路

赛后填坑系列QAQ

贴代码呀

 #include<iostream>
 #include<algorithm>
 #include<cstdio>
 #include<cstdlib>
 #include<cstring>
 #include<string>

 using namespace std;

 void setIO(const string& a) {
     freopen((a+".in").c_str(), "r", stdin);
     freopen((a+".out").c_str(), "w", stdout);
 }

 const int N =  + , INF = ~0u>>;

 int n;
 #include<vector>
 struct Edge{
     int to, w;
     Edge(int to = , int w = ) : to(to), w(w) {}
 };
 vector<Edge> G[N], G2[N];

 void AddEdge(int u, int v, int w) {
     G[u].push_back(Edge(v, w));
     G2[v].push_back(Edge(u, w));
 }

 int dis[N];

 #include<queue>
 namespace SPFA {
     int* d;
     bool inq[N];
     queue<int> q;

     void insert(int x, int dis) {
         if(d[x] <= dis) return;
         d[x] = dis;
         if(!inq[x]) q.push(x), inq[x] = ;
     }

     void main(int st, int dis[], const vector<Edge> G[]) {
         d = dis;
         for(int i = ; i <= n; i++) {
             d[i] = INF;
             inq[i] = ;
         }
         insert(st, );
         while(!q.empty()) {
             int u = q.front(); q.pop(); inq[u] = ;
             for(unsigned i = ; i < G[u].size(); i++) {
                 insert(G[u][i].to, d[u] + G[u][i].w);
             }
         }
     }
 }

 struct Node {
     int g, h, v;
     Node(int g = , int h = , int v = ) : g(g), h(h), v(v) {}
     bool operator < (const Node& rhs) const {
         return h > rhs.h;
     }
 };

 namespace A_star {
     priority_queue<Node> q;
     int inq[N];

     int main(int st, int ed, int k) {
         if(dis[st] == INF) return -;
         if(st == ed) k++;

         q.push(Node(,  + dis[st], st));
         while(!q.empty()) {
             Node cur = q.top(); q.pop();
             int u = cur.v;

             inq[u]++;
             if(inq[ed] == k) return cur.g;
             if(inq[u] > k) continue; // mark1

             for(unsigned i = ; i < G[u].size(); i++) {
                 const Edge& e = G[u][i];
                 q.push(Node(cur.g + e.w, cur.g + e.w + dis[e.to], e.to));
             }
         }
         return -;
     }
 }

 int main() {
 #ifdef DEBUG
     freopen("in.txt", "r", stdin);
     freopen("out.txt", "w", stdout);
 #endif

     int m, k, st, ed;
     scanf("%d%d", &n, &m);
     for(int i = ; i <= m; i++) {
         int u, v, w;
         scanf("%d%d%d", &u, &v, &w);
         AddEdge(u, v, w);
     }

     scanf("%d%d%d", &st, &ed, &k);

     SPFA::main(ed, dis, G2);
     printf("%d\n", A_star::main(st, ed, k));

     return ;
 }