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\n", 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\n";
}
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;
}
拙いものと思えども、
その手に握る其れこそが、
いつか幻想を生んでいく。