Abandoned warehouse

input/code.cpp: In function 'int main()':
input/code.cpp:41:23: warning: variable 'bx' set but not used [-Wunused-but-set-variable]
   41 |     int n, m, ax, ay, bx, by;
      |                       ^~
input/code.cpp:41:27: warning: variable 'by' set but not used [-Wunused-but-set-variable]
   41 |     int n, m, ax, ay, bx, by;
      |                           ^~
input/code.cpp:59:8: warning: 'ay' may be used uninitialized in this function [-Wmaybe-uninitialized]
   59 |     bfs(map, ax, ay, n, m);
      |     ~~~^~~~~~~~~~~~~~~~~~~
input/code.cpp:59:8: warning: 'ax' may be used uninitialized in this function [-Wmaybe-uninitialized]

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

void bfs(vector<vector<char>>& map, int ax, int ay, int n, int m) {
    queue<pair<pair<int, int>, string>> q;
    q.push(make_pair(make_pair(ax, ay), ""));
    
    vector<pair<int, int>> directions = {{-1, 0}, {1, 0}, {0, -1}, {0, 1}};
    vector<char> directionChars = {'U', 'D', 'L', 'R'};
    
    map[ax][ay] = '#';

    while (!q.empty()) {
        auto aux = q.front();
        q.pop();

        int nx = aux.first.first, ny = aux.first.second;

        for (int i = 0; i < 4; ++i) {
            int newX = nx + directions[i].first;
            int newY = ny + directions[i].second;
            if (newX >= 0 && newX < n && newY >= 0 && newY < m && map[newX][newY] != '#') {
                q.push(make_pair(make_pair(newX, newY), aux.second + directionChars[i]));
                if (map[newX][newY] == 'B') {
                    cout << "YES" << endl;
                    cout << aux.second.size() + 1 << endl;
                    cout << aux.second + directionChars[i] << endl;
                    return;
                }
                map[newX][newY] = '#';
            }
        }
    }

    cout << "NO" << endl;
}

int main() {
    int n, m, ax, ay, bx, by;

    cin >> n >> m;

    vector<vector<char>> map(n, vector<char>(m));
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < m; ++j) {
            cin >> map[i][j];
            if (map[i][j] == 'A') {
                ax = i;
                ay = j;
            } else if (map[i][j] == 'B') {
                bx = i;
                by = j;
            }
        }
    }

    bfs(map, ax, ay, n, m);
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: TIME LIMIT EXCEEDED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED