poj2449 Remmarguts' Date-k短路+A*（待解决）

原题链接：​​http://poj.org/problem?id=2449​​

一直RE，找不到解决，以后再看。

#define _CRT_SECURE_NO_DEPRECATE

#include<iostream>
#include<vector>
#include<cstring>
#include<queue>
#include<stack>
#include<algorithm>
#include<cmath>
#include<string>
#include<stdio.h>
#define INF 1000000000
#define eps 0.0001
using namespace std;

struct P
{
  int v, w;
  int next;
};

struct Node
{
  int v;
  int f, g;
  bool operator<(const Node& node)const
  {
    if (node.f == f) return g > node.g;
    return f > node.f;
  }
};

int cnt;
int n, m;
int s, t, k;
bool vis[1005];
int Q[1005];//模拟队列
int dis[1005];
int head[1005];
int rhead[1005];
P p[500005];
P rp[500005];

void add(int u, int v, int w)
{
  p[cnt].v = v;
  p[cnt].next = head[u];
  p[cnt].w = w;
  head[u] = cnt;

  rp[cnt].v = u;
  rp[cnt].next = rhead[v];
  rp[cnt].w = w;
  rhead[v] = cnt++;
}

void spfa(int src)
{
  memset(vis, 0, sizeof(vis));
  for (int i = 1; i <= n; i++)
    dis[i] = INF;

  int down = 0;
  int up = 1;
  Q[down] = src;//模拟队列
  dis[src] = 0;
  vis[src] = 1;
  
  while (down<up)
  {
    int u = Q[down++];
    vis[u] = 0;
    for (int i = rhead[u]; i != -1; i = rp[i].next)
    {
      int v = rp[i].v;
      if (dis[v] > dis[u] + rp[i].w)
      {
        dis[v] = dis[u] + rp[i].w;
        if (vis[v]) continue;
        Q[up++] = v;
        vis[v] = 1;
      }
    }
  }
}

int aStar(int src, int dst)
{
  if (dis[src] == INF)//根本无法连通，直接就是-1
    return -1;

  priority_queue<Node> pq;
  int kk = 0;

  if (src == dst)
    kk++;

  Node node;
  Node node1;
  node.v = src;
  node.g = 0;
  node.f = node.g + dis[src];

  pq.push(node);
  while (!pq.empty())
  {
    node = pq.top();
    pq.pop();
    if (node.v == dst)
    {
      kk++;
      if (kk == k)
        return node.g;
    }
    for (int i = head[node.v]; i!=-1; i=p[i].next)
    {
      node1.v = p[i].v;
      node1.g = node.g + p[i].w;
      node1.f = node1.g + dis[node.v];
      pq.push(node1);
    }
  }
  return -1;
}

int main() 
{
  while (~scanf("%d%d", &n, &m))
  {
    cnt = 0;
    memset(head, -1, sizeof(head));
    memset(rhead, -1, sizeof(rhead));

    int u, v, w;
    for (int i = 1; i <= m; i++)
    {
      scanf("%d%d%d", &u, &v, &w);
      add(u, v, w);
    }

    scanf("%d%d%d", &s, &t, &k);
    spfa(t);
    printf("%d\n", aStar(s, t));
  }
  return 0;
}