[LeetCode] 4. Median of Two Sorted Arrays

There are two sorted arrays nums1 and nums2 of size m and n respectively. 

public class Solution {
    public double findMedianSortedArrays(int[] nums1, int[] nums2) {
        int total = nums1.length + nums2.length;
        if (total % 2 == 1) {
            return findKth(nums1, 0, nums1.length, nums2, 0, nums2.length, total / 2 + 1);
        } else {
            return (findKth(nums1, 0, nums1.length, nums2, 0, nums2.length, total / 2) + findKth(nums1, 0, nums1.length, nums2, 0, nums2.length, total / 2 + 1)) * 1.0 / 2;
        }
    }
    
    private int findKth(int[] n1, int s1, int len1, int[] n2, int s2, int len2, int K) {
        if (len1 > len2) {
            return findKth(n2, s2, len2, n1, s1, len1, K);
        }
        if (len1 == 0) {
            return n2[s2 + K - 1];
        }
        if (K == 1) {
            return Math.min(n1[s1], n2[s2]);
        }
        int pa = Math.min(len1, K / 2);
        int pb = K - pa;
        if (n1[s1 + pa - 1] < n2[s2 + pb - 1]) {
            return findKth(n1, s1 + pa, len1 - pa, n2, s2, len2, K - pa);
        } else if (n1[s1 + pa - 1] > n2[s2 + pb - 1]) {
            return findKth(n1, s1, len1, n2, s2 + pb, len2 - pb, pa);
        } else {
            return n1[s1 + pa - 1];
        }
    }
}