4. Median of Two Sorted Arrays

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

题目大意

输入两个有序数组，找到两个数组的中间数，若数组大小为奇数就返回正中间的那个数，否则返回正中间两个数的平均值

解题思路

题目虽然有说时间复杂度必须为O(log (m+n))，可是好像并没有这个限制，直接合并两个数组，然后从小到大排序，取中间数即可

AC代码

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
double findMedianSortedArrays(vector<int>& nums1, vector<int>& nums2) {
    nums1.insert(nums1.end(), nums2.begin(), nums2.end());                  //合并两个数组
    sort(nums1.begin(), nums1.end());                                       //排序
    int n = nums1.size() / 2;       
    if(nums1.size() % 2 != 0) return nums1[n];
    else return (nums1[n] + nums1[n - 1]) * 1.0 / 2;
}
int main() {
    vector<int> nums1 = {1};
    vector<int> nums2 = {2};
    double ans = findMedianSortedArrays(nums1, nums2);
    cout << ans;
    return 0;
}