A_star poj2449 k短路

赛后填坑系列QAQ

贴代码呀

  1 #include<iostream>
  2 #include<algorithm>
  3 #include<cstdio>
  4 #include<cstdlib>
  5 #include<cstring>
  6 #include<string>
  7 
  8 using namespace std;
  9 
 10 void setIO(const string& a) {
 11     freopen((a+".in").c_str(), "r", stdin);
 12     freopen((a+".out").c_str(), "w", stdout);
 13 }
 14 
 15 const int N = 1000 + 10, INF = ~0u>>2;
 16 
 17 int n;
 18 #include<vector>
 19 struct Edge{
 20     int to, w;
 21     Edge(int to = 0, int w = 0) : to(to), w(w) {}
 22 };
 23 vector<Edge> G[N], G2[N];
 24 
 25 void AddEdge(int u, int v, int w) {
 26     G[u].push_back(Edge(v, w));
 27     G2[v].push_back(Edge(u, w));
 28 }
 29 
 30 int dis[N];
 31 
 32 #include<queue>
 33 namespace SPFA {
 34     int* d;
 35     bool inq[N];
 36     queue<int> q;
 37     
 38     void insert(int x, int dis) {
 39         if(d[x] <= dis) return;
 40         d[x] = dis;
 41         if(!inq[x]) q.push(x), inq[x] = 1;
 42     }
 43     
 44     void main(int st, int dis[], const vector<Edge> G[]) {
 45         d = dis;
 46         for(int i = 1; i <= n; i++) {
 47             d[i] = INF;
 48             inq[i] = 0;
 49         }
 50         insert(st, 0);
 51         while(!q.empty()) {
 52             int u = q.front(); q.pop(); inq[u] = 0;
 53             for(unsigned i = 0; i < G[u].size(); i++) {
 54                 insert(G[u][i].to, d[u] + G[u][i].w);
 55             }
 56         }
 57     }
 58 }
 59 
 60 struct Node {
 61     int g, h, v;
 62     Node(int g = 0, int h = 0, int v = 0) : g(g), h(h), v(v) {}
 63     bool operator < (const Node& rhs) const {
 64         return h > rhs.h;
 65     }
 66 };
 67 
 68 namespace A_star {
 69     priority_queue<Node> q;
 70     int inq[N];
 71     
 72     int main(int st, int ed, int k) {
 73         if(dis[st] == INF) return -1;
 74         if(st == ed) k++;
 75         
 76         q.push(Node(0, 0 + dis[st], st));
 77         while(!q.empty()) {
 78             Node cur = q.top(); q.pop();
 79             int u = cur.v;
 80             
 81             inq[u]++;
 82             if(inq[ed] == k) return cur.g;
 83             if(inq[u] > k) continue; // mark1
 84             
 85             for(unsigned i = 0; i < G[u].size(); i++) {
 86                 const Edge& e = G[u][i];
 87                 q.push(Node(cur.g + e.w, cur.g + e.w + dis[e.to], e.to));
 88             }
 89         }
 90         return -1;
 91     }
 92 }
 93 
 94 int main() {
 95 #ifdef DEBUG
 96     freopen("in.txt", "r", stdin);
 97     freopen("out.txt", "w", stdout);
 98 #endif
 99     
100     int m, k, st, ed;
101     scanf("%d%d", &n, &m);
102     for(int i = 1; i <= m; i++) {
103         int u, v, w;
104         scanf("%d%d%d", &u, &v, &w);
105         AddEdge(u, v, w);
106     }
107     
108     scanf("%d%d%d", &st, &ed, &k);
109     
110     SPFA::main(ed, dis, G2);
111     printf("%d\n", A_star::main(st, ed, k));
112     
113     return 0;
114 }

 

posted @ 2015-11-20 10:27  Showson  阅读(143)  评论(0)  编辑  收藏  举报