c ++算法为什么无限循环

Question

I was trying to solve a problem on the algorithm site and asked a question because I couldn't catch the error.

I can't understand why the infinite loop goes. My algorithmic logic is correct. Because if you remove the while in the main statement and print it for each case, the infinite loop does not run.

The problem site is below. can you help me?

https://www.acmicpc.net/problem/11370

#include <iostream>
#include <vector>
#include <queue>
#include <tuple>
#include <string>
using namespace std;
int w, h;
int dx[]= {0, 0, -1, 1};
int dy[]= {1, -1, 0, 0};

void bfs (vector<string> &board, vector< vector<bool> > &check, int x, int y) {
    if (check[y][x] || board[y][x] != 'S') {
        return ;
    }
    check[y][x] = true;
    queue< pair<int, int> > q;
    q.push(make_pair(x, y));
    
    while(!q.empty()) {
        int _x, _y;
        tie(_x, _y) = q.front(); q.pop();

        for (int i=0; i<4; i++) {
            int nx = _x + dx[i];
            int ny = _y + dy[i];
            
            if (nx>=0 && nx<w && ny>=0 && ny<h) {
                if (check[ny][nx])
                    continue;
                if (board[ny][nx] == 'T') {
                    board[ny][nx] = 'S';
                    check[ny][nx] = true;
                    q.push(make_pair(nx, ny));
                }
            }
        }
    }
    return ;
}

int main() {
  while (true) {
    cin >> h >> w;
    if (h==0 && w==0) {
        break;
    }
    cout << h << w;
    vector<string> board(h);
    vector< vector<bool> > check(h, vector<bool>(w, false));
    for (int i=0; i<h; i++) {
        cin >> board[i];
    }
    for (int k=0; k<h; k++) {
        for (int l=0; l<w; l++) {
            bfs(board, check, l, k);
        }
    }

    for (int k=0; k<h; k++) {
      cout << board[k] << endl;
    }
  }
  return (0);
}

input

3 4
T..
TST
..T
TTT
5 5
T.T.T
.T.T.
..S..
.T.T.
T.T.T
0 0

output

Answer 1

输入首先给出宽度，而不是高度。

    cin >> w >> h;