Leetcode 74 Search a 2D Matrix

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.

 

class Solution(object):
    def searchMatrix(self, matrix, target):
        if not matrix:
            return False
        rn = 0
        for i in range(len(matrix)):
            if matrix[i][0] > target:
                break
            rn = i
        
        for x in matrix[rn]:
            if x == target:
                return True
        return False