LeetCode #4 : Median of Two Sort

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

首先保证两个vector都不为空，其次将两个vector里面较小的一半加入到一个新的vector中，判断两个vector容器的size和是否为偶数，若是则对末尾两个求平均数，否则直接返回末尾数。

double findMedianSortedArrays(vector<int>& nums1, vector<int>& nums2) {
    int nums_length = nums1.size() + nums2.size();
    if (nums_length==0)return 0;
    if (nums1.size() == 0) {
        nums1.push_back(nums2.back());
        nums2.pop_back();
    }
    if (nums2.size() == 0) {
        nums2.push_back(nums1.back());
        nums1.pop_back();
    }
    vector<int> nums;
    int i = 0, j = 0;
    nums1.push_back(INT_MAX);
    nums2.push_back(INT_MAX);
    while ((i + j) <= (nums_length >> 1)) {
        if (nums1[i] > nums2[j]) {
            nums.insert(nums.end(),nums2[j]);
            j++;
        }else{
            nums.insert(nums.end(), nums1[i]);
            i++;
        }
    }
    if ((nums_length & 1) == 0) {
        int last = nums.back();
        nums.pop_back();
        last += nums.back();
        return 1.0*last / 2;
    }
    return nums.back();
}