BFS迷宫，水题

BFS，没啥可多说的
http://hncu.acmclub.com/index.php?app=problem_title&id=111&problem_id=1102

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<queue>
#include<stack>
#include<math.h>
#include<vector>
#include<algorithm>
#include<iostream>

using namespace std;

const int N = 105;
const int M = 105;
const int inf = 1000000007;
const int mod = 1000000007;

char map[N][M];
int vis[N][M];

int n,m;
int sx,sy,ex,ey;
int steps;

struct node{
    int x;
    int y;
    int step;
};

int dir[4][2]={{-1,0},{1,0},{0,-1},{0,1}};

bool judge(int i,int j){
    if(i>=1&&i<=n && j>=1&&j<=m &&map[i][j]!='#'&& vis[i][j]==0)return true;
    else return false;
}

void BFS(){
    queue<node> q;
    node s,a,next;
    s.x=sx;
    s.y=sy;
    s.step=0;
    vis[sx][sy]=1;

    q.push(s);///始点入队
    while(!q.empty()){
        a=q.front();///取队首
        q.pop();///删除队首

        for(int i=0;i<=3;i++){///访问四个方向
            next.x=a.x+dir[i][0];
            next.y=a.y+dir[i][1];
            next.step=a.step+1;///这三排建立下一个访问点信息

            if(judge(next.x,next.y)){///是否能通过
                q.push(next);
                vis[next.x][next.y]=1;
            }

            if(map[next.x][next.y]=='E'){///是否结束
                steps=next.step;
                return;
            }
        }
    }
    steps=-1;
}

int main()
{
    int T;
    cin>>T;
    while(T--){
        cin>>n>>m;
        steps=0;
        memset(vis,0,sizeof(vis));
        for(int i=1;i<=n;i++){
            for(int j=1;j<=m;j++){
                cin>>map[i][j];
                if(map[i][j]=='S'){sx=i;sy=j;}
                if(map[i][j]=='E'){ex=i;ey=j;}
            }
        }
        BFS();
        cout<<steps<<endl;
    }
    return 0;
}