_S -> E #不可通过 求最短距离 无输出-1 _

输入样例：
3
3 4
.S..
###.
..E.
3 4
.S..
.E..
....
3 4
.S..
####
..E.

bfs 队列（queue）

C++ 代码

#include <bits/stdc++.h>
using namespace std;
const int N = 2e2+10;
int n,m,xi[] = {1,0,-1,0},yi[] = {0,1,0,-1};
int a[N][N],b[N][N];
int ans = 1e3,ret = 0;
struct str {
    int x,y;
};
int bfs (str fist){
    memset(b,-1,sizeof(b));
    queue<str> q;
    q.push(fist);
    b[fist.x][fist.y] = 0;
    while(q.size()){
        auto t = q.front();
        q.pop();

        for(int i = 0; i < 4 ; i++){
            int x = t.x + xi[i],y = t.y + yi[i];
            if(x >= 1 && y >= 1 && x <= n && y <= m && a[x][y] && b[x][y] == -1){
                b[x][y] = b[t.x][t.y] + 1;
                q.push({x,y});
                if(a[x][y] == 2 ) return b[x][y]; 
            }
        }
    }
    return -1;
}
int main(){
    int t;
    cin >> t;
    while(t--){
        memset (a, 0 ,sizeof(a));
        cin >>n >> m;
        ans = 1000;ret = 0;
        int r,c;char ch;
        str fist;
        for(int i = 1; i <= n; i++){
            for(int j = 1; j <= m; j++){
                cin >> ch;
                if(ch == 'E') a[i][j] = 2;
                else if(ch == 'S') fist.x = i,fist.y = j;
                else if(ch == '.') a[i][j] = 1;
            }
        }
        ans = bfs(fist);
        if( ans == -1) cout <<"oop!"<<endl;
        else cout<< ans <<endl;
    }
    return 0;
}