leetcode-daily/Dec/30_Magic_Squares_In_Grid.cpp at master · abhishekpaturkar/leetcode-daily · GitHub

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// 840. Magic Squares In Grid

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

class Solution
{
    bool isValid(int i, int j, vector<vector<int>> &grid)
    {
        vector<int> count(10, 0);
        for (int x = 0; x < 3; ++x)
        {
            for (int y = 0; y < 3; ++y)
            {
                int num = grid[i + x][j + y];
                if (num < 1 || num > 9 || count[num] > 0)
                    return false;
                count[num]++;
            }
        }

        int sum = grid[i][j] + grid[i][j + 1] + grid[i][j + 2];

        for (int x = 0; x < 3; ++x)
        {
            if (sum != (grid[i + x][j] + grid[i + x][j + 1] + grid[i + x][j + 2]))
                return false;
        }

        for (int y = 0; y < 3; ++y)
        {
            if (sum != (grid[i][j + y] + grid[i + 1][j + y] + grid[i + 2][j + y]))
                return false;
        }

        if (sum != (grid[i][j] + grid[i + 1][j + 1] + grid[i + 2][j + 2]))
            return false;
        if (sum != (grid[i + 2][j] + grid[i + 1][j + 1] + grid[i][j + 2]))
            return false;

        return true;
    }

public:
    int numMagicSquaresInside(vector<vector<int>> &grid)
    {
        int cnt = 0;
        int row = grid.size();
        int col = grid[0].size();

        if (row < 3 || col < 3)
            return 0;

        for (int i = 0; i <= row - 3; ++i)
        {
            for (int j = 0; j <= col - 3; ++j)
            {
                if (isValid(i, j, grid))
                    cnt++;
            }
        }
        return cnt;
    }
};