HDU 3152 obstacle course (priority queue, extensive search)

题目

 

用优先队列优化普通的广搜就可以过了。

 

 

#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;}

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HDU 3152 Obstacle Course（优先队列，广搜）