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 = 1000 + 10, INF = ~0u>>2;

int n;
#include<vector>
struct Edge{
    int to, w;
    Edge(int to = 0, int w = 0) : 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] = 1;
    }
    
    void main(int st, int dis[], const vector<Edge> G[]) {
        d = dis;
        for(int i = 1; i <= n; i++) {
            d[i] = INF;
            inq[i] = 0;
        }
        insert(st, 0);
        while(!q.empty()) {
            int u = q.front(); q.pop(); inq[u] = 0;
            for(unsigned i = 0; 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 = 0, int h = 0, int v = 0) : 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 -1;
        if(st == ed) k++;
        
        q.push(Node(0, 0 + 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 = 0; 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 -1;
    }
}

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 = 1; 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
", A_star::main(st, ed, k));
    
    return 0;
}