HDU 3152 Obstacle Course（优先队列，广搜）

#include<stdio.h>
#include<string.h>
#include<algorithm>
using namespace std;
#include<queue>
struct pq
{
    int x,y,val;
    friend bool operator < (pq a,pq b)
    {
        return a.val > b.val;
    }

};

priority_queue <pq> q;

int xx[4]={0,0,1,-1};
int yy[4]={1,-1,0,0};
int n;
int mp[130][130],vis[130][130];
int i,j,k;
int bfs(int x,int y)
{
    if(x==n-1&&y==n-1)return mp[x][y];
    while(!q.empty())q.pop();
    memset(vis,0,sizeof(vis));
    pq topp;
    topp.x=x;topp.y=y;topp.val=mp[x][y];
    q.push(topp);
    vis[x][y]=1;
    while(!q.empty())
    {
        pq tmp=q.top();
        q.pop();
        vis[tmp.x][tmp.y]=1;
        for(i=0;i<4;i++)
        {
            pq nxt;
            nxt.x=tmp.x+xx[i];
            nxt.y=tmp.y+yy[i];
            nxt.val=tmp.val+mp[nxt.x][nxt.y];
            if(vis[nxt.x][nxt.y]==0&&nxt.x>=0&&nxt.y>=0&&nxt.x<n&&nxt.y<n){
                if(nxt.x==n-1&&nxt.y==n-1)return nxt.val;
                q.push(nxt);
            }
            
        }
    }
}
int main()
{
    int id=1;
    while(scanf("%d",&n),n)
    {
        for(i=0;i<n;i++)
        {
            for(j=0;j<n;j++){
                scanf("%d",&mp[i][j]);
            }
        }
        printf("Problem %d: %d\n",id++,bfs(0,0));
    }
    system("pause");
    return 0;
}