原题地址：https://oj.leetcode.com/problems/search-a-2d-matrix/

题意：

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.

解题思路：类似于二分查找。

代码：

class Solution:    # @param matrix, a list of lists of integers    # @param target, an integer    # @return a boolean    def searchMatrix(self, matrix, target):        i = 0; j = len(matrix[0]) - 1        while i < len(matrix) and j >= 0:            if matrix[i][j] == target: return True            elif matrix[i][j] > target: j -= 1            else: i += 1        return False