LeetCode4 ：median of two sorted arrays---求两个有序数组的中位数

Posted 2020-10-08

class Solution {
public:
    double FindKthNumber(vector<int> numbers1, vector<int>numbers2, int len1, int len2, int start1, int start2, int k){
    
        if (len1 > len2)
            return    FindKthNumber(numbers2, numbers1, len2, len1, start2, start1, k);
        if (len1 == 0)
            return numbers2[start2 + k - 1];
        if (k == 1)
            return min(numbers1[start1], numbers2[start2]);
        int p1 = min(k / 2, len1);
        int p2 = k - p1;
        if (numbers1[start1 + p1 - 1] < numbers2[start2 + p2 - 1])
            return FindKthNumber(numbers1, numbers2, len1 - p1, len2, start1 + p1, start2, k - p1);
        else if (numbers1[start1 + p1 - 1] > numbers2[start2 + p2 - 1])
            return FindKthNumber(numbers1, numbers2, len1, len2 - p2, start1, start2 + p2, k - p2);
        else
            return numbers1[start1 + p1 - 1];
    }
    double findMedianSortedArrays(vector<int>& nums1, vector<int>& nums2) {
        int len1=nums1.size();
        int len2=nums2.size();
        int k=(len1+len2)/2;
        if((len1+len2)%2==0)
            return (FindKthNumber(nums1,nums2,len1,len2,0,0,k)+FindKthNumber(nums1,nums2,len1,len2,0,0,k+1))/2;
        else
            return FindKthNumber(nums1,nums2,len1,len2,0,0,k+1);
        
    }
};