题解

#include<bits/stdc++.h>
#define N 1010
using namespace std;

int n,m;
int dir[4][2]={{0,1},{1,0},{0,-1},{-1,0}};
char Map[N][N];
int visited[N][N];
bool inmap(int X,int Y){
    char obj=Map[X][Y];
    return X>=1 and X<=n and Y>=1 and Y<=m and (obj=='.' || obj=='S' || obj=='T') and visited[X][Y]==0;
}
void dfs(int x,int y){
    if (x==n and y==m) return;
    for (int i=0;i<4;i++){
        int X=x+dir[i][0];
        int Y=y+dir[i][1];
        if (inmap(X,Y)){
            visited[X][Y]=1;
            dfs(X,Y);
        }
    }
}
int main(){
    cin>>n>>m;
    for (int i=1;i<=n;i++){
        for (int j=1;j<=m;j++){
            cin>>Map[i][j];
        }
    }
    visited[1][1]=1;
    dfs(1,1);
    cout<<(visited[n][m]==1?"YES":"NO");
    return 0;
}