Package g0801_0900.s0840_magic_squares_in_grid

Class Solution

java.lang.Object
g0801_0900.s0840_magic_squares_in_grid.Solution
public class Solution extends java.lang.Object
840 - Magic Squares In Grid.

Medium

A 3 x 3 magic square is a 3 x 3 grid filled with distinct numbers from 1 to 9 such that each row, column, and both diagonals all have the same sum.

Given a row x col grid of integers, how many 3 x 3 “magic square” subgrids are there? (Each subgrid is contiguous).

Example 1:

Input: grid = [[4,3,8,4],[9,5,1,9],[2,7,6,2]]

Output: 1

Explanation: The following subgrid is a 3 x 3 magic square: while this one is not: In total, there is only one magic square inside the given grid.

Example 2:

Input: grid = [[8]]

Output: 0

Constraints:

  • row == grid.length
  • col == grid[i].length
  • 1 <= row, col <= 10
  • 0 <= grid[i][j] <= 15

  • Constructor Summary

    Constructors
    Constructor
    Description
    Solution()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    int
    numMagicSquaresInside(int[][] grid)
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • numMagicSquaresInside

      public int numMagicSquaresInside(int[][] grid)