Leetcode 2373 Largest Local Values in a Matrix Solution in Java | Hindi Coding Community

 

You are given an n x n integer matrix grid.

Generate an integer matrix maxLocal of size (n - 2) x (n - 2) such that:

• maxLocal[i][j] is equal to the largest value of the 3 x 3 matrix in grid centered around row i + 1 and column j + 1.

In other words, we want to find the largest value in every contiguous 3 x 3 matrix in grid.

Return the generated matrix.

 

Example 1:

Input: grid = [[9,9,8,1],[5,6,2,6],[8,2,6,4],[6,2,2,2]]
Output: [[9,9],[8,6]]
Explanation: The diagram above shows the original matrix and the generated matrix.
Notice that each value in the generated matrix corresponds to the largest value of a contiguous 3 x 3 matrix in grid.

Example 2:

Input: grid = [[1,1,1,1,1],[1,1,1,1,1],[1,1,2,1,1],[1,1,1,1,1],[1,1,1,1,1]]
Output: [[2,2,2],[2,2,2],[2,2,2]]
Explanation: Notice that the 2 is contained within every contiguous 3 x 3 matrix in grid.

 

Constraints:

• n == grid.length == grid[i].length
• 3 <= n <= 100
• 1 <= grid[i][j] <= 100

Java Code :

public int[][] largestLocal(int[][] grid) {

int[][] result = new int[grid.length - 2][grid.length - 2];

for (int i = 0; i < result.length; ++i) {

for (int j = 0; j < result.length; ++j) {

int largest = Integer.MIN_VALUE;

for (int row = i; row < i + 3; ++row) {

for (int column = j; column < j + 3; ++column) {

largest = Math.max(largest, grid[row][column]);

}

}

result[i][j] = largest;

}

}

return result;

}