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. 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.从右上角开始看。
class Solution { public boolean searchMatrix(int[][] matrix, int target) { if (matrix == null || matrix.length == 0) { return false; } int row = 0; int col = matrix[0].length - 1; while (row < matrix.length && col >= 0) { if (matrix[row][col] < target) { row++; } else if (matrix[row][col] > target) { col--; } else { return true; } } return false; } }