Write an efficient algorithm that searches for a value in an m x n matrix. This 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.
For example,
Consider the following 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] ]
Given target = 5, return true.
Given target = 20, return false.
1 Solution 1. Binary Search 2 // The matrix is divided into 3 parts: smaller, bigger and unknown. 3 public class Solution { 4 public boolean searchMatrix(int[][] matrix, int target) { 5 int m = matrix.length; 6 int n = matrix[0].length; 7 int i = 0, j = n-1; 8 while (i<m && j>=0) { 9 if (target == matrix[i][j]) return true; 10 if (matrix[i][j] > target) { 11 j--; 12 }else if (matrix[i][j] < target) { 13 i++; 14 } 15 } 16 17 return false; 18 } 19 }