《搜索》hdoj 1242 bfs+优先队列

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<queue>
using namespace std; char map[205][205]; int visit[205][205]; int dir[4][2]={{-1,0},{1,0},{0,1},{0,-1}}; int n,m; struct node { int x,y; int time; friend bool operator < (const node &a,const node &b) { return a.time>b.time; } }; int check(int x,int y) { if(x>=0&&y>=0&&y<m&&x<n&&map[x][y]!='#') return 1; return 0; } int bfs(int x,int y) { int i;
    node st,ed;
    priority_queue<node>que;
    memset(visit,0,sizeof(visit));
    st.x=x;
    st.y=y;
    st.time=0;
    visit[st.x][st.y]=1;
    que.push(st); while(!que.empty()) {
        st=que.top();
        que.pop(); if(map[st.x][st.y]=='r') return st.time; for(i=0;i<4;i++) {
            ed.x=st.x+dir[i][0];
            ed.y=st.y+dir[i][1]; if(check(ed.x,ed.y)&&!visit[ed.x][ed.y]) {
                visit[ed.x][ed.y]=1; if(map[ed.x][ed.y]=='x')
                    ed.time=st.time+2; else
                    ed.time=st.time+1;
                que.push(ed); } } } return -1; } int main() { int i,j,x,y,ans; while(scanf("%d%d",&n,&m)!=EOF) { for(i=0;i<n;i++)
            scanf("%s",map[i]); for(i=0;i<n;i++) for(j=0;j<m;j++) if(map[i][j]=='a') {
                    x=i;
                    y=j; break; }
        ans=bfs(x,y); if(ans==-1)
            printf("Poor ANGEL has to stay in the prison all his life.\n"); else
            printf("%d\n",ans); } return 0; }