poj2449 Remmarguts' Date K短路 A*

K短路裸题。

#include <algorithm>
#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;
struct Edge{
    int too, nxt, val;
}edge[100005];
struct Odge{
    int too, nxt, val;
}odge[100005];
struct Node{
    int idd, hfc, gfc;
    bool operator<(const Node &x)const{
        return hfc+gfc>x.hfc+x.gfc;
    }
}d[1000005];//n*k
int n, m, s, t, k, uu, vv, ww, hea[1005], oea[1005], cnt, ont, dis[1005];
int din, tms[1005], ans;
bool vis[1005];
void add_edge(int fro, int too, int val){
    edge[++cnt].nxt = hea[fro];
    edge[cnt].too = too;
    edge[cnt].val = val;
    hea[fro] = cnt;
}
void add_odge(int fro, int too, int val){
    odge[++ont].nxt = oea[fro];
    odge[ont].too = too;
    odge[ont].val = val;
    oea[fro] = ont;
}
void dijkstra(){
    memset(dis, 0x3f, sizeof(dis));
    dis[t] = 0;
    for(int i=1; i<=n; i++){
        int mini=0;
        for(int j=1; j<=n; j++)
            if(!vis[j] && dis[mini]>dis[j])
                mini = j;
        vis[mini] = true;
        if(!mini)   return ;
        for(int i=oea[mini]; i; i=odge[i].nxt){
            int v=odge[i].too;
            dis[v] = min(dis[v], odge[i].val+dis[mini]);
        }
    }
}
void aStar(){
    d[++din] = (Node){s, 0, 0};
    while(din){
        Node j=d[1];
        pop_heap(d+1, d+1+din);
        din--;
        tms[j.idd]++;
        if(j.idd==t && tms[t]==k){
            printf("%d
", j.hfc+j.gfc);
			return ;
        }
        if(tms[j.idd]>k)    continue;
        for(int i=hea[j.idd]; i; i=edge[i].nxt)
			if(tms[edge[i].too]<=k){
    	        d[++din] = (Node){edge[i].too, j.hfc+edge[i].val, dis[edge[i].too]};
        	    push_heap(d+1, d+1+din);
        	}
    }
	cout<<"-1
";
}
int main(){
    cin>>n>>m;
    for(int i=1; i<=m; i++){
        scanf("%d %d %d", &uu, &vv, &ww);
        add_edge(uu, vv, ww);
        add_odge(vv, uu, ww);
    }
	cin>>s>>t>>k;
	if(s==t)	k++;
    dijkstra();
    aStar();
    return 0;
}