[Graphs Basic](https://cses.fi/problemset/task/1193/)

Problems and Contests
#1

Question Link : Graphs Basic
My Solution :

#include <bits/stdc++.h>
using namespace std;

void solve() {
	int m , n;
	cin >> m >> n;
	vector<vector<char>> arr(m, vector<char>(n));
	vector<vector<string>> vis(m, vector<string>(n, "X"));
	int sx, sy , ex , ey;
	for (int i = 0 ; i < m ; i++) {
		for (int j = 0 ; j < n ; j++) {
			char ch;
			cin >> ch;
			arr[i][j] = ch;
			if (ch == 'A') {
				sx = i;
				sy = j;
			}
			if (ch == 'B') {
				ex = i;
				ey = j;
			}
		}
	}
	int dx[] = { -1, 1, 0, 0};
	int dy[] = {0, 0, 1, -1};
	queue<pair<int, int>> q;
	q.push({sx, sy});
	vis[sx][sy] = "";
	while (!q.empty()) {
		auto top = q.front();
		q.pop();
		int x = top.first;
		int y = top.second;
		// cout << x << " " << y << "\n";
		for (int k = 0 ; k < 4 ; k++) {
			int xx = x + dx[k];
			int yy = y + dy[k];
			if (xx >= 0 and xx<m and yy >= 0 and yy < n and vis[xx][yy] == "X" and arr[xx][yy] != '#') {
				q.push({xx, yy});
				if (k == 0) vis[xx][yy] = vis[x][y] + "U";
				if (k == 1) vis[xx][yy] = vis[x][y] + "D";
				if (k == 2) vis[xx][yy] = vis[x][y] + "R";
				if (k == 3) vis[xx][yy] = vis[x][y] + "L";
			}
		}
	}
	if (vis[ex][ey] == "X") {
		cout << "NO\n";
	} else {
		cout << "YES\n";
		cout << int(vis[ex][ey].size()) << "\n";
		cout << vis[ex][ey] << "\n";
	}

}

int main() {
#ifndef ONLINE_JUDGE
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);
#endif
	solve();
	return 0;
}

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image693×568 56.5 KB

Dont know why i am getting Runtime error

#2

Have you tried running the test cases on your own machine?

#3

yes they are running

#4

Have you checked that all of your vector indices are within bounds? You can replace the [] with .at() to make sure everything is within bounds.