Selamatkan Putri

#include <cmath>
#include <cstdio>
#include <cstring>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

int point = 2147483647, x, y;

bool dfs (vector<string> labirin, int i, int j, int poin) {
    if (i < 0 || j < 0 || i >= y || j >= x) return false;
    if (labirin[i][j] == '#') return false;
    if (labirin[i][j] == 'P') {
        if (poin < point) point = poin;
        return true;
    }
    labirin[i][j] = '#';
    bool b = false;
    b |= dfs(labirin, i + 1, j, poin + 1);
    b |= dfs(labirin, i, j + 1, poin + 1);
    b |= dfs(labirin, i - 1, j, poin + 1);
    b |= dfs(labirin, i, j - 1, poin + 1);
    return b;
}

int main() {
    cin >> y >> x;
    int m = 0, n = 0;
    vector<string> v(y);
    for (int i = 0; i < y; i++) {
        cin >> v[i];
        for (int j = 0; j < x; j++) {
            if (v[i][j] == 'B') {
                m = i;
                n = j;
            }
        }
    }
    bool b = dfs(v, m, n, 0);
    if (b) cout << point;
    else cout << -1;
}