hdu 2612 Find a way（BFS）

#include<stdio.h>
#include<string.h>
#include<queue>
#include<algorithm>
#define N 205
using namespace std;
char map[N][N];
int v[N][N],ans1[N][N],ans2[N][N],d[4][2] = { {-1,0},{1,0},{0,-1},{0,1} };
int x1,x2,y1,y2,n,m,num;
struct node
{
    int x,y,step;
    friend bool operator < (node a,node b)
    {
        return a.step > b.step;
    }
};
void bfs1(int x,int y,int total)//total表示KFC的總數目
{
    memset(ans1,1,sizeof(ans1));
    memset(v,0,sizeof(v));
    priority_queue <node> q;
    node s,temp;
    s.x = x;
    s.y = y;
    s.step = 0;
    v[x][y] = 1;
    q.push(s);
    while(!q.empty())
    {
        temp = q.top();
        q.pop();
        if(map[temp.x][temp.y] == '@')
        {
            ans1[temp.x][temp.y] = temp.step;
            total -- ;
        }
        if(total == 0) return;//所有的KFC都已經計算過
        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] || map[s.x][s.y] == '#')
             continue;
            v[s.x][s.y] = 1;
            s.step ++;
            q.push(s);
        }
    }
}
void bfs2(int x,int y,int total)
{
    memset(ans2,1,sizeof(ans2));
    memset(v,0,sizeof(v));
    priority_queue <node> q;
    node s,temp;
    s.x = x;
    s.y = y;
    s.step = 0;
    v[x][y] = 1;
    q.push(s);
    while(!q.empty())
    {
        temp = q.top();
        q.pop();
        if(map[temp.x][temp.y] == '@')
        {
            ans2[temp.x][temp.y] = temp.step;
            total -- ;
        }
        if(total == 0) 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] || map[s.x][s.y] == '#')
             continue;
            v[s.x][s.y] = 1;
            s.step ++;
            q.push(s);
        }
    }
}
int main()
{
    int i,j;
    while(~scanf("%d%d",&n,&m))
    {
        num = 0;
        for(i = 0 ; i < n ; i ++)
        {
            scanf("%s",map[i]);
            for(j = 0 ; j < m ; j ++)
            {
                if(map[i][j] == 'Y')
                {
                    x1 = i;
                    y1 = j;
                }
                else if(map[i][j] == 'M')
                {
                    x2 = i;
                    y2 = j;
                }
                else if(map[i][j] == '@')
                 num++;
            }
        }
        bfs1(x1,y1,num);
        bfs2(x2,y2,num);
        int sum = 10000000;
        for(i = 0 ; i < n ; i ++)
        for(j = 0 ; j < m ; j ++)
        if(map[i][j] == '@')
        {
            sum = min(sum,ans1[i][j] + ans2[i][j]);
        }
        printf("%d\n",sum * 11);
    }
    return 0;
}