LeetCode # Array # Easy # 88. Merge Sorted Array

Question: Merge two sorted arrays into one

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

Note:

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

Idea: According to the solution in the offer, start from the end of the two arrays and add them in descending order until all array 2 is copied into array 1.

1  class Solution {
 2      public  void merge( int [] nums1, int m, int [] nums2, int n) {
 3          m = m - 1 ;//m,n is now used as an index value
 4          n = n - 1 ;
 5          int i = m + n + 1 ;
 6          while (m >= 0 || n >= 0 ){
 7              if (m < 0 ){//Indicates that nums1 has been compared, and the remaining value of nums2 is added to nums1 empty space in front.
8                  nums1[i--] = nums2[n-- ];
 9              } else  if (n < 0) {//Indicates that nums2 has been compared, and the previous ones of nums1 are already in order, so exit directly.
10                  break; 11              } else {
 12                  nums1[i--] = nums1[m] > nums2[n] ? nums1[m--] : nums2[n-- ];
 13              }
 14          }
 15      }
 16 }

Reference: https://segmentfault.com/a/1190000003707411