hdu 1548 简单 dijstra

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
#include<queue>
using namespace std;
const int maxn=202;
const int INF=1<<29;
int n,st,ed,k[maxn],map[maxn][maxn],dis[maxn],vis[maxn];
struct Node
{
    int v,next,w;
    bool operator < (const Node &a) const
    {
        return w > a.w;
    }
} Edge[2000002],t1,t2;
int dijstra(int  st,int ed)
{
    priority_queue<Node>q;
    for(int i=1; i<=n; i++)
    {
        dis[i]=INF;
        if(map[st][i]<dis[i])
        {
            dis[i] = map[st][i];
            t1.w = dis[i];
            t1.v =  i;
            q.push(t1);
        }
    }
    dis[st]=0;//此句没加错了2次，囧~~~
    vis[st] = 1;
    while(!q.empty())
    {
        t1 = q.top();
        q.pop();
        int u = t1.v;
        if(vis[u]) continue;
        vis[u] = 1;
        for(int v=1; v<=n; v++)
        {
            if(!vis[v])
            {
                if(dis[v]>dis[u]+map[u][v])
                {
                    dis[v] =dis[u]+map[u][v];
                    t2.v = v;
                    t2.w = dis[v];
                    q.push(t2);
                }
            }
        }
    }
    if(dis[ed]>=INF)return -1;
    return dis[ed];
}
int main()
{
    while(scanf("%d",&n),n)
    {
        scanf("%d%d",&st,&ed);
        int i,j;
        for(i=1;i<=n;i++)
        {
            for(j=1;j<=n;j++)
            {
                map[i][j]=INF;
            }
            map[i][i]=0;
        }
        memset(vis,0,sizeof(vis));
        for(i=1;i<=n;i++)
        {
            scanf("%d",&k[i]);
            if(i-k[i]>=1)map[i][i-k[i]]=1;
            if(i+k[i]<=n)map[i][i+k[i]]=1;
        }
        printf("%d\n",dijstra(st,ed));
    }
    return 0;
}