UVA11624 Fire!

来源：互联网发布：北京赛车pk10辅助软件编辑：程序博客网时间：2024/05/16 14:32
AC代码：
#include <iostream>#include <cstdio>#include <cstring>#include <string>#include <queue>using namespace std;struct node{    int x,y;    int t;    bool operator < (const node &a)const{        return t > a.t;    }};const int dx[] = {-1,0,1,0},dy[] = {0,-1,0,1};int n,m;char maze[1005][1005];int visj[1005][1005],visf[1005][1005];void bfs1(){    memset(visf,-1,sizeof(visf));    node cur;    queue<node> q;    for(int i = 0; i < n; i++){        for(int j = 0; j < m; j++){            if(maze[i][j] == 'F'){                visf[i][j] = 0;                q.push(node{i,j,0});            }        }    }    while(!q.empty()){        cur = q.front();        q.pop();        for(int i = 0; i < 4; i++){            int xx = cur.x+dx[i],yy = cur.y+dy[i];            if(xx < 0 || xx >= n || yy < 0 || yy >= m || visf[xx][yy] != -1)                continue;            if(maze[xx][yy] != '#'){                visf[xx][yy] = visf[cur.x][cur.y]+1;                q.push(node{xx,yy,visf[xx][yy]});            }        }    }}int bfs2(int x,int y){    memset(visj,-1,sizeof(visj));    node cur;    visj[x][y] = 0;    priority_queue<node> q;    q.push(node{x,y,0});    while(!q.empty()){        cur = q.top();        q.pop();        if(cur.x == 0 || cur.x == n-1 || cur.y == 0 || cur.y == m-1){            return cur.t+1;        }        for(int i = 0; i < 4; i++){            int xx = cur.x+dx[i],yy = cur.y+dy[i];            if(xx < 0 || xx >= n || yy < 0 || yy >= m || visj[xx][yy] != -1)                continue;            if(visf[xx][yy] != -1 && visj[cur.x][cur.y]+1 >= visf[xx][yy])                continue;            if(maze[xx][yy] != '#'){                visj[xx][yy] = visj[cur.x][cur.y]+1;                q.push(node{xx,yy,visj[xx][yy]});            }        }    }    return -1;}int main(){    int T;    scanf("%d",&T);    while(T--){        int jx,jy,fx,fy;        scanf("%d%d",&n,&m);        for(int i = 0; i < n; i++){            scanf("%s",maze[i]);            for(int j = 0; j < m; j++){                if(maze[i][j] == 'J'){                    jx = i;jy = j;                }            }        }        bfs1();//模拟火蔓延,尼玛这题有毒呀，火的位置不止一个        int ans = bfs2(jx,jy);//模拟人        if(ans < 0)            printf("IMPOSSIBLE\n");        else            printf("%d\n",ans);    }    return 0;}
0 0