为何MLE

#include <iostream>
#include <queue>
using namespace std;

int r, c;
char mp[31][31];
bool cxk[31][31][31][31];
int dgx[4] = { 1, -1, 0, 0 };
int dgy[4] = { 0, 0, 1, -1 };
int dmx[4] = { 1, -1, 0, 0 };
int dmy[4] = { 0, 0, -1, 1 };

struct node
{
	int gx, gy, mx, my, t;
};

int bfs(node nd)
{
	queue<node> qnd;
	qnd.push(nd);

	while (!qnd.empty())
	{
		node nnd = qnd.front();
		qnd.pop();

		if (mp[nnd.gx][nnd.gy] == 'T' && mp[nnd.mx][nnd.my] == 'T')
		{
			return nnd.t;
		}

		for (int i = 0; i < 4; i++)
		{
			int lgx = nnd.gx + dgx[i];
			int lgy = nnd.gy + dgy[i];
			int lmx = nnd.mx + dmx[i];
			int lmy = nnd.my + dmy[i]; 
			if (lgx < 0 || lgx >= r || lgy < 0 || lgy >= c || lmx < 0 || lmx >= r || lmy < 0 || lmy >= c)
			{
				continue;
			}
			if ((mp[lgx][lgy] == '#' && mp[lmx][lmy] == '#') || mp[lgx][lgy] == 'X' || mp[lmx][lmy] == 'X' || cxk[lgx][lgy][lmx][lmy])
			{
				continue;
			}

			if (mp[lgx][lgy] == '#')
			{
				lgx = nnd.gx;
				lgy = nnd.gy;
			}
			else if (mp[lmx][lmy] == '#')
			{
				lmx = nnd.mx;
				lmy = nnd.my;
			}

			cxk[lgx][lgy][lmx][lmy] = true;
			qnd.push({lgx, lgy, lmx, lmy, nnd.t + 1});
		}
	}
	return -1;
}

int main()
{
	int gx, gy, mx, my;
	cin >> r >> c;
	for (int i = 0; i < r; i++)
	{
		for (int j = 0; j < c; j++)
		{
			cin >> mp[i][j];
			if (mp[i][j] == 'G')
			{
				gx = i;
				gy = j;
			}
			if (mp[i][j] == 'M')
			{
				mx = i;
				my = j;
			}
		}
	}
	cxk[gx][gy][mx][my] = true;
	int ans = bfs({ gx, gy, mx, my, 0});
	if (ans > 0)
	{
		cout << ans << endl;
	}
	else
	{
		cout << "no" << endl;
	}
	return 0;
}