First, the array --- merge two ordered arrays

Given two ordered arrays of integers and nums2 nums1, incorporated into the nums2 nums1 in an ordered array such as a num1.

Description:

And initializing the number of elements nums1 nums2 of m and n.
You can assume nums1 sufficient space (space equal to or greater than m + n) to save the elements of nums2.
Example:

Input:
nums1 = [1,2,3,0,0,0], m =. 3
nums2 = [2,5,6], n-=. 3

Output: [1,2,2,3,5,6]

Thinking

Directly to the largest, from the back to put elements traversed once completed

. 1  class Solution {
 2  public :
 . 3      void Merge (Vector < int > & nums1, int m, Vector < int > & nums2, int n-) {
 . 4          // directly to the largest 
. 5          for ( int I = m + N- . 1 , i_1 = M- . 1 , = N- i_2 are used . 1 ; I> = 0 ; i-- ) {
 . 6              // nums1 empty array, i = n-1, i_1 = 0-1 = -1, i_2 = n-1 
. 7              IF (i_1 < 0 ) {
 . 8                  nums1 [I] = nums2 [i_2 are used];
 . 9                 i_2--;//同nums1[i]=nums2[i_2--];
10                 continue;
11             }
12             //nums2空数组, n=0, i=m-1, i_1=m-1, i_2=0-1=-1
13             if(i_2<0){
14                 nums1[i] = nums1[i_1];
15                 i_1--;
16                 continue;
17             }
18             if(nums1[i_1] >= nums2[i_2]){
19                 nums1[i]=nums1[i_1];
20                 i_1--;
21             }
22              else {
 23                  nums1 [i] = nums2 [I_2];
24                  i_2-- ;
25              }
 26              
27          }
 28      }
 29 };