Median of Two Sorted Arrays

Question:

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)).

Solution:

double findk(vector<int> nums1,vector<int> nums2,int k)
{
    int M=nums1.size();
    int N=nums2.size();
    if(M>N) return findk(nums2,nums1,k);
    else
    {
        if(nums1.empty())  return nums2[k-1];
        if(k==1) return min(nums1[k-1],nums2[k-1]);
        int ia=min(k/2,M);
        int ib=k-ia;
        if(nums1[ia-1]<nums2[ib-1])
        {
            vector<int> tmp1(nums1.begin()+ia,nums1.end());
            vector<int> tmp2(nums2.begin(),nums2.end());
            return findk(tmp1,tmp2,k-ia);
        }
        else if(nums1[ia-1]>nums2[ib-1])
        {
            vector<int> tmp1(nums1.begin(),nums1.end());
            vector<int> tmp2(nums2.begin()+ib,nums2.end());
            return findk(tmp1,tmp2,k-ib);
        }
        else 
        {
            return nums1[ia-1];
        }
    }
}
class Solution {
public:
    double findMedianSortedArrays(vector<int>& nums1, vector<int>& nums2)
{
    int M=nums1.size();
    int N=nums2.size();
    int total=M+N;
    if(total%2!=0)
        return findk(nums1,nums2,total/2+1);
    else
        return (findk(nums1,nums2,total/2)+findk(nums1,nums2,total/2+1))/2.0;
}
};