201312-5 I’m stuck!

#include <iostream>
using namespace std;
const int N = 60;
int n, m;
char g[N][N];
bool st1[N][N], st2[N][N];
int dx[] = {-1, 0, 1, 0}, dy[] = {0, 1, 0, -1};
bool check(int x, int y, int k)
{
    char c = g[x][y];
    if (c == 'S' || c == 'T' || c == '+') return true;
    if (c == '-' && k % 2 == 1) return true;
    if (c == '|' && k % 2 == 0) return true;
    if (c == '.' && k == 2) return true;
    return false;
}
void dfs1(int x, int y)
{
    st1[x][y] = true;
    for (int i = 0; i < 4; i ++ )
    {
        int a = x + dx[i], b = y + dy[i];
        if (a < 0 || a >= n || b < 0 || b >= m) continue;
        if (g[a][b] == '#') continue;
        if (st1[a][b]) continue;
        if (check(x, y, i)) 
            dfs1(a, b);
    }
}
void dfs2(int x, int y)
{
    st2[x][y] = true;
    for (int i = 0; i < 4; i ++ ) 
    {
        int a = x + dx[i], b = y + dy[i];
        if (a < 0 || a >= n || b < 0 || b >= m) continue;
        if (g[a][b] == '#') continue;
        if (st2[a][b]) continue;
        if (check(a, b, i ^ 2)) 
            dfs2(a, b);
    }
}
int main()
{
    cin >> n >> m;
    for (int i = 0; i < n; i ++ ) cin >> g[i];
    int x, y;
    for (int i = 0; i < n; i ++ ) 
        for (int j = 0; j < m; j ++ ) 
            if (g[i][j] == 'S') dfs1(i, j);
            else if (g[i][j] == 'T')
            {
                x = i, y = j;
                dfs2(i, j);
            }
    if (!st1[x][y]) puts("I'm stuck!");
    else
    {
        int res = 0;
        for (int i = 0; i < n; i ++ ) 
            for (int j = 0; j < m; j ++ ) 
                if (st1[i][j] && !st2[i][j])
                    res ++;
        cout << res << endl;
    }
    return 0;
}