LeetCodeOJ——4. Median of Two Sorted Arrays-优快云博客

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)).

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

错误方法：将两个有序数组合并（类似于有序链表的合并），然后根据数字总数的奇偶性求出中位数。虽然这通过了，但却不满足时间复杂度，时间复杂度为O(m+n)。

错误方法代码：

class Solution {
public:
    double findMedianSortedArrays(vector<int>& nums1, vector<int>& nums2) {
        int len1=nums1.size();
        int len2=nums2.size();
        vector<int> nums(len1+len2);
        int i=0,j=0,k=0;
        while(i<len1&&j<len2){
            if(nums1[i]<nums2[j]){
                nums[k]=nums1[i];
                i++;k++;
            }
            else{
                nums[k]=nums2[j];
                j++;k++;
            }
        }
        while(i<len1){
            nums[k++]=nums1[i++];
        }
        while(j<len2){
            nums[k++]=nums2[j++];
        }
        if((len1+len2)%2==0){
            return ((double)nums[(len1+len2)/2-1]+(double)nums[(len1+len2)/2])/2.0;
        }
        else{
            return (double)nums[(len1+len2)/2];
        }
    }
};