Leetcode|有序数组合并|4. 寻找两个正序数组的中位数

class Solution {
public:
    double findMedianSortedArrays(vector<int>& nums1, vector<int>& nums2) {
        vector<int> merge;
        int size1 = nums1.size();
        int size2 = nums2.size();
        int sizem = size1 + size2;
        int l1 = 0, l2 = 0;
        // 1.合并2个有序数组，合并完即为有序，O(n)复杂度
        while (l1 < size1 || l2 < size2) {
            if (l1 == size1) merge.emplace_back(nums2[l2++]);
            else if (l2 == size2) merge.emplace_back(nums1[l1++]);
            else if (nums1[l1] < nums2[l2]) 
                merge.emplace_back(nums1[l1++]);
            else if (nums1[l1] >= nums2[l2])
                merge.emplace_back(nums2[l2++]);
        }
        // 2.偶数个，则取两个的一半；奇数个则直接取中间索引对应值
        if (sizem % 2 == 0)
            return merge[sizem / 2 - 1] + (merge[sizem / 2] - merge[sizem / 2 - 1]) * 1.0 / 2;
        return merge[sizem / 2];
    }
};