hdu 2822 Dogs（优先队列）

题目链接：hdu2822

会优先队列话这题很容易AC。。。。

#include<stdio.h>#include<string.h>#include<queue>#include<algorithm>#define N 1005using namespace std;char map[N][N];int v[N][N],d[4][2] = { {-1,0},{1,0},{0,-1},{0,1} };int begin_x,begin_y,end_x,end_y,n,m;struct node{    int x,y,step;    friend bool operator < (node a,node b)    {        return a.step > b.step;    }};void bfs(){    memset(v,0,sizeof(v));    priority_queue <node> q;    node s,temp;    s.x = begin_x;    s.y = begin_y;    s.step = 0;    v[s.x][s.y] = 1;    q.push(s);    while(!q.empty())    {        temp = q.top();        q.pop();        if(s.x == end_x && s.y == end_y)        {            printf("%d\n",s.step);            return ;        }        for(int i= 0 ; i < 4 ; i ++)        {            s = temp;            s.x += d[i][0];            s.y += d[i][1];            if(s.x < 0 || s.x >= n || s.y < 0 || s.y >= m || v[s.x][s.y])             continue;            v[s.x][s.y] = 1;            if(map[s.x][s.y] == '.') s.step ++;            q.push(s);        }    }}int main(){    int i;    while(scanf("%d%d",&n,&m) && (n + m))    {        for(i = 0 ; i < n ; i ++)         scanf("%s",map[i]);        scanf("%d%d%d%d",&begin_x,&begin_y,&end_x,&end_y);        begin_x -- ; begin_y --; end_x -- ; end_y --;//题目给出的坐标都是从1开始计算的        bfs();    }    return 0;}