求最少单位时间，用bfs较佳
bfs找到一条合法路径

#include <iostream>
#include <cstring>
#include <cstdio>
#include <algorithm>
#include <queue>
#define x first
#define y second

using namespace std;
typedef pair<int, int> PII;
const int N = 210;
int n,m;
char g[N][N];
int d[N][N];
int dx[4] = {-1,0,1,0},dy[4] = {0,1,0,-1};
int bfs(PII start,PII end){
    queue<PII> q;
    memset(d,-1,sizeof d);
    d[start.x][start.y] = 0;
    q.push(start);
    while(q.size()){
        auto t = q.front();
        q.pop();
        for(int i = 0;i < 4;++i){
            int x = t.x + dx[i],y = t.y + dy[i];
            if(x < 0 || x >= n || y < 0 || y >= m)  continue;
            if(g[x][y] == '#')  continue;
            if(d[x][y] != -1)   continue;
            d[x][y] = d[t.x][t.y] + 1;
            if(end == make_pair(x,y))   return d[x][y];
            q.push({x,y});
        }
    }
    return -1;
}

int main(){
    int T;
    scanf("%d",&T);
    while(T--){
        scanf("%d%d",&n,&m);
        for(int i = 0;i < n;++i)    scanf("%s",g[i]);
        PII start,end;
        for(int i = 0;i < n;++i){
            for(int j = 0;j < m;++j){
                if(g[i][j] == 'S')  start = {i,j};
                else if(g[i][j] == 'E')  end = {i,j};
            }
        }
        int dist = bfs(start,end);
        if(dist == -1)  printf("oop!\n");
        else    printf("%d\n",dist);
    }
    return 0;
}