Leetcode 88 Merge Sorted Array

Given two sorted integer arrays nums1 and nums2, merge nums2 into nums1 as one sorted array.

Note:
You may assume that nums1 has enough space (size that is greater or equal to m + n) to hold additional elements from nums2. The number of elements initialized in nums1and nums2 are m and n respectively.

Solution 1: use merge sort in place from end to start is the key.

 public class Solution {  
   public void merge(int[] nums1, int m, int[] nums2, int n) {  
     int i=m-1, j=n-1, k=m+n-1;  
     while (i>=0 || j>=0) {  
       if (i<0) nums1[k--]=nums2[j--];  
       else if (j<0) nums1[k--]=nums1[i--];  
       else if (nums1[i]<nums2[j]) nums1[k--]=nums2[j--];  
       else nums1[k--]=nums1[i--];  
     }  
   }  
 }