2464: 中山市选[2009]小明的游戏

来源：互联网发布：茶杯淘宝编辑：程序博客网时间：2024/05/01 10:18

题目链接

题目大意：棋盘，求最短路

题解：spfa

我的收获：水水水

#include<cstdio>#include<queue>int n,m,x1,y1,x2,y2;char s[505][505];int l[505][505];bool in[505][505];struct pos{    int x,y;};std::queue<pos>q;int xs[]={-1,0,1,0};int ys[]={0,-1,0,1};int main(){    while(1){        scanf("%d%d",&n,&m);        if(n+m==0)break;        for(int i=1;i<=n;i++)scanf("%s",s[i]+1);        scanf("%d%d%d%d",&x1,&y1,&x2,&y2);        for(int i=1;i<=n;i++){            for(int j=1;j<=m;j++){                l[i][j]=2147483647;            }        }        l[++x1][++y1]=0;        q.push((pos){x1,y1});        while(!q.empty()){            pos w=q.front();q.pop();            int x=w.x,y=w.y;            in[x][y]=0;            for(int i=0;i<4;i++){                int xx=x+xs[i],yy=y+ys[i];                if(!s[xx][yy])continue;                if(s[xx][yy]!=s[x][y]){                    if(l[x][y]+1<l[xx][yy]){                        l[xx][yy]=l[x][y]+1;                        if(!in[xx][yy])q.push((pos){xx,yy}),in[xx][yy]=1;                    }                }else{                    if(l[x][y]<l[xx][yy]){                        l[xx][yy]=l[x][y];                        if(!in[xx][yy])q.push((pos){xx,yy}),in[xx][yy]=1;                    }                }            }        }        printf("%d\n",l[x2+1][y2+1]);    }    return 0;}

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