004.md

4. Median of Two Sorted Arrays

难度: Hard

刷题内容

原题连接

• https://leetcode.com/problems/median-of-two-sorted-arrays/description/

内容描述

There are two sorted arrays nums1 and nums2 of size m and n respectively.

Find the median of the two sorted arrays. The overall run time complexity should be O(log (m+n)).

You may assume nums1 and nums2 cannot be both empty.

Example 1:

nums1 = [1, 3]
nums2 = [2]

The median is 2.0
Example 2:

nums1 = [1, 2]
nums2 = [3, 4]

The median is (2 + 3)/2 = 2.5

解题方案

思路 1 - 时间复杂度: O(lg(m+n)) - 空间复杂度: O(1)

class Solution(object):
    def findMedianSortedArrays(self, nums1, nums2):
        """
        :type nums1: List[int]
        :type nums2: List[int]
        :rtype: float
        """
        nums1.extends(nums2)
        nums1.sort()
        lens = len(nums1)
        if lens%2 == 0:
            mid = (nums1[lens//2-1] + nums1[lens//2]) / 2
        else:
            mid = nums1[lens//2]
        return mid

总结：

1. 准确说这解法是不符合题意的，真正的时间复杂度优化到题目要求还真得好好研究官方讲解，不过先放过，有空再细细琢磨