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 from left to right.
- The first integer of each row is greater than the last integer of the previous row.
For example,
Consider the following matrix:
[ [1, 3, 5, 7], [10, 11, 16, 20], [23, 30, 34, 50] ]
Given target = 3, return true.
1 public class Solution { 2 public boolean searchMatrix(int[][] matrix, int target) { 3 int m = matrix.length, n = matrix[0].length; 4 if(m == 0 || n == 0) return false; 5 int i = m-1,j = 0; 6 while(i >= 0 && j < n){ 7 if(matrix[i][j] == target) return true; 8 if(matrix[i][j] > target) i--; 9 else j++; 10 } 11 return false; 12 } 13 }
该题矩阵也是有特点的。 对比题目：
http://www.cnblogs.com/guoguolan/p/5620209.html
解法二： 可以使用二分查找做，不过应该没有利用矩阵的特点来做速度快。