CCF 201312-5 I’m stuck! (暴力，BFS)

#pragma comment(linker, "/STACK:1024000000,1024000000")
#include <cstdio>
#include <string>
#include <cstdlib>
#include <cmath>
#include <iostream>
#include <cstring>
#include <set>
#include <queue>
#include <algorithm>
#include <vector>
#include <map>
#include <cctype>
#include <cmath>
#include <stack>
#define frer freopen("in.txt", "r", stdin)
#define frew freopen("out.txt", "w", stdout)
using namespace std;

typedef long long LL;
typedef pair<int, int> P;
const int INF = 0x3f3f3f3f;
const double inf = 0x3f3f3f3f3f3f;
const double PI = acos(-1.0);
const double eps = 1e-8;
const int maxn = 50 + 5;
const int mod = 1e9 + 7;
const int dr[] = {-1, 1, 0, 0};
const int dc[] = {0, 0, 1, -1};
const char *de[] = {"0000", "0001", "0010", "0011", "0100", "0101", "0110", "0111", "1000", "1001", "1010", "1011", "1100", "1101", "1110", "1111"};
int n, m;
const int mon[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
const int monn[] = {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
inline int Min(int a, int b){ return a < b ? a : b; }
inline int Max(int a, int b){ return a > b ? a : b; }
inline LL Min(LL a, LL b){ return a < b ? a : b; }
inline LL Max(LL a, LL b){ return a > b ? a : b; }
inline bool is_in(int r, int c){
    return r >= 0 && r < n && c >= 0 && c < m;
}
char s[maxn][maxn];
int vis[maxn][maxn];
int viss[maxn][maxn];

void bfs1(int x, int y){
    queue<P> q;
    q.push(P(x, y));
    vis[x][y] = 1;
    while(!q.empty()){
        P u = q.front();   q.pop();
        int x = u.first, y = u.second;
        for(int i = 0; i < 4; ++i){
            int xx = x + dr[i];
            int yy = y + dc[i];
            if(!is_in(xx, yy) || vis[xx][yy] || s[xx][yy] == ‘#‘)  continue;
            if(s[x][y] == ‘-‘ && (0 == i || 1 == i))  continue;
            if(s[x][y] == ‘|‘ && (2 == i || 3 == i))  continue;
            if(s[x][y] == ‘.‘ && (0 == i || 2 == i || 3 == i))  continue;
            vis[xx][yy] = 1;
            q.push(P(xx, yy));
        }
    }
}

bool bfs(int x, int y){
    queue<P> q;
    q.push(P(x, y));
    memset(viss, 0, sizeof viss);
    viss[x][y] = 1;
    while(!q.empty()){
        P u = q.front();   q.pop();
        int x = u.first, y = u.second;
        if(s[x][y] == ‘T‘)  return false;
        for(int i = 0; i < 4; ++i){
            int xx = x + dr[i];
            int yy = y + dc[i];
            if(!is_in(xx, yy) || s[xx][yy] == ‘#‘ || viss[xx][yy])  continue;
            if(s[x][y] == ‘-‘ && (0 == i || 1 == i))  continue;
            if(s[x][y] == ‘|‘ && (2 == i || 3 == i))  continue;
            if(s[x][y] == ‘.‘ && (0 == i || 2 == i || 3 == i))  continue;
            viss[xx][yy] = 1;
            q.push(P(xx, yy));
        }
    }
    return true;
}

int main(){
    scanf("%d %d", &n, &m);
    for(int i = 0; i < n; ++i)  scanf("%s", s[i]);
    memset(vis, 0, sizeof vis);
    int sx, sy, tx, ty;
    for(int i = 0; i < n; ++i){
        for(int j = 0; j < m; ++j){
            if(s[i][j] == ‘S‘)  sx = i, sy = j;
            else if(s[i][j] == ‘T‘)   tx = i, ty = j;
        }
    }
    bfs1(sx, sy);
    if(!vis[tx][ty]) {  puts("I‘m stuck!");  return 0; }
    int ans = 0;
    for(int i = 0; i < n; ++i){
        for(int j = 0; j < m; ++j){
            if(vis[i][j] == 1 && bfs(i, j))  ++ans;
        }
    }

    printf("%d\n", ans);
    return 0;
}