hdu 2612 Find a way

#include<iostream>
#include<queue>
#include<cstring>
#define maxn 200+5
using namespace std;
int m,n,ax,ay,bx,by;
char mapp[maxn][maxn];
int visit[maxn][maxn];
int rem1[maxn][maxn];
int rem2[maxn][maxn];
int dir[4][2]={{0,1},{0,-1},{1,0},{-1,0}};
struct stu
{
int x,y,s,sign;
};
void bfs(int x,int y,int sign)
{
stu xx,yy;
queue<stu>root;
xx.x=x;xx.y=y;xx.s=0;xx.sign=sign;
visit[xx.x][xx.y]=1;
root.push(xx);
while(root.size())
{
xx=root.front();
root.pop();
if(mapp[xx.x][xx.y]=='@'&&xx.sign==1){rem1[xx.x][xx.y]=xx.s;}
else if(mapp[xx.x][xx.y]=='@'&&xx.sign==2){rem2[xx.x][xx.y]=xx.s;}
for(int i=0;i<4;i++)
{
yy.x=xx.x+dir[i][0];
yy.y=xx.y+dir[i][1];
yy.s=xx.s;
yy.sign=xx.sign;
if(yy.x<0||yy.x>=n||yy.y<0||yy.y>=m||visit[yy.x][yy.y]||mapp[yy.x][yy.y]=='#'){continue;}
yy.s++;
root.push(yy);
visit[yy.x][yy.y]=1;
}
}
}
int main()
{
while(cin>>n>>m)
{
for(int i=0;i<n;i++)
{
for(int j=0;j<m;j++)
{
cin>>mapp[i][j];
if(mapp[i][j]=='Y') ax=i,ay=j;
if(mapp[i][j]=='M') bx=i,by=j;
}
}
memset(visit,0,sizeof(visit));
memset(rem1,0,sizeof(rem1));
bfs(ax,ay,1);
memset(visit,0,sizeof(visit));
memset(rem2,0,sizeof(rem2));
bfs(bx,by,2);
int sum=1<<20;
for(int i=0;i<n;i++)
{
for(int j=0;j<m;j++)
{
if((rem1[i][j]!=0)&&(rem2[i][j]!=0)) sum=min(sum,rem1[i][j]+rem2[i][j]);
}
}
cout<<sum*11<<endl;
}
return 0;
}