![https://leetcode.com/problems/search-a-2d-matrix-ii/]

Write an efficient algorithm that searches for a target value in an m x n integer matrix. The matrix has the following properties:

  • Integers in each row are sorted in ascending from left to right.
  • Integers in each column are sorted in ascending from top to bottom.

ex1

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Example 1:

Input: matrix = [[1,4,7,11,15],[2,5,8,12,19],[3,6,9,16,22],[10,13,14,17,24],[18,21,23,26,30]], target = 5
Output: true

ex2

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Example 2:

Input: matrix = [[1,4,7,11,15],[2,5,8,12,19],[3,6,9,16,22],[10,13,14,17,24],[18,21,23,26,30]], target = 20
Output: false

Constraints:

  • m == matrix.length
  • n == matrix[i].length
  • 1 <= n, m <= 300
  • -109 <= matix[i][j] <= 109
  • All the integers in each row are sorted in ascending order.
  • All the integers in each column are sorted in ascending order.
  • -109 <= target <= 109
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class Solution {
    
    public boolean searchMatrix(int[][] matrix, int target) {
        int n = matrix.length;
        int m = matrix[0].length;
        
        int i = 0;
        int j = m - 1;
        
        while (i < n && j >= 0 ) {
            if (target < matrix[i][j]) {
                j--;
            } else if (target > matrix[i][j]) {
                i++;
            } else {
                return true;
            }
        }
        
        return false;
    }
}