Count Unguarded Cells in the Grid

class Solution {
public:
    int countUnguarded(int m, int n, vector<vector<int>>& guards, vector<vector<int>>& walls) {
        // Initialize grid with zeros
        int g[m][n];
        memset(g, 0, sizeof(g));
        
        // Mark guards and walls as 2
        for (auto& e : guards) {
            g[e[0]][e[1]] = 2;
…    }
};