poj 2449 第k短路

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#include<queue>
using namespace std;

const int maxn = 1005;
const int maxe = 100050;
const int INF = 0x3f3f3f3f;

struct Edge{
int v,w;
int next;
Edge(int v=0,int w=0,int next=0):
v(v),  w(w), next(next){}
};
struct Heap{
int u,f,g;
Heap(int u=0,int f=0,int g=0): u(u), f(f), g(g){}
bool operator < (const Heap& rhs) const{
return f > rhs.f;
}
};
int dist[maxn];

struct Dijkstra{
Edge edges[maxe];
int head[maxn],cnt;
bool vis[maxn];

void init(){
memset(head,-1,sizeof(head));
cnt = 0;
}

void addedge(int u,int v,int w){
edges[cnt] = Edge(v,w,head[u]);
head[u] = cnt++;
}

void solve(int s){
memset(vis,0,sizeof(vis));
memset(dist,0x3f,sizeof(dist));
priority_queue<Heap> Q;
Q.push(Heap(s,0,0));
dist[s] = 0;

while(!Q.empty()){
Heap temp = Q.top(); Q.pop();
int u = temp.u;
int d = temp.f;
if(vis[u])  continue;
vis[u] = true;
for(int i=head[u];i!=-1;i=edges[i].next){
Edge& e = edges[i];
if(dist[e.v] > d + e.w){
dist[e.v] = d + e.w;
Q.push(Heap(e.v,dist[e.v],0));
}
}
}
}
}solver1;

struct A_Star{
Edge edges[maxe];
int head[maxn],cnt;
int num[maxn];

void init(){
memset(head,-1,sizeof(head));
cnt = 0;
}

void addedge(int u,int v,int w){
edges[cnt] = Edge(v,w,head[u]);
head[u] = cnt++;
}

int solve(int s,int t,int k){
memset(num,0,sizeof(num));
priority_queue<Heap> Q;
if(dist[s] >= INF)  return -1;
Q.push(Heap(s,dist[s],0));

while(!Q.empty()){
Heap temp = Q.top();  Q.pop();
int u = temp.u;
num[u]++;
if(num[t] == k){
return temp.f;
}
if(num[u] > k){
continue;
}
for(int i=head[u];i!=-1;i=edges[i].next){
Edge& e = edges[i];
int g = temp.g + e.w;
int f = g + dist[e.v];
Q.push(Heap(e.v,f,g));
}
}
return -1;
}
}solver2;

int main()
{
//freopen("E:\\acm\\input.txt","r",stdin);
int N,M;
cin>>N>>M;
solver1.init();
solver2.init();
for(int i=1;i<=M;i++){
int u,v,w;
scanf("%d %d %d",&u,&v,&w);
solver1.addedge(v,u,w);
solver2.addedge(u,v,w);
}
int s,t,k;
scanf("%d %d %d",&s,&t,&k);
solver1.solve(t);
if(s == t)  k++;
int ans = solver2.solve(s,t,k);
printf("%d\n",ans);
}