88. Merge Sorted Array

## Example
Input: nums1 = [1,2,3,0,0,0], m = 3, nums2 = [2,5,6], n = 3
Output: [1,2,2,3,5,6]
Explanation: The arrays we are merging are [1,2,3] and [2,5,6].
The result of the merge is [1,2,2,3,5,6] with the underlined elements coming from nums1.

You are given two integer arrays nums1 and nums2, sorted in non-decreasing order, and two integers m and n, representing the number of elements in nums1 and nums2 respectively.

Merge nums1 and nums2 into a single array sorted in non-decreasing order.

Solution:

class Solution {
    public void merge(int[] nums1, int m, int[] nums2, int n) {
       /**
       1: find the biggest element in both array 
       2: populate the largest one into nums1 array
       3: if there are still some element in nums2, just put into nums1 array 
        */
        int len1 = m - 1;
        int len2 = n - 1;
        int finalLen = m + n -1;
        while(len1 >= 0 && len2 >= 0){
            nums1[finalLen--] = (nums1[len1] > nums2[len2]) ? 
                                nums1[len1--] : nums2[len2--];
            
        }
        while(len2 >= 0){
            nums1[finalLen--] = nums2[len2--];
        }
}

Tips: 

1: The name of the variable name, can't name the key word like: "final, class"

2: make the different of 

nums1[resultLen--] = (nums1[len1] > nums2[len2]) ?
                            nums1[len1--] : nums2[len2--];


# the same as:
if(nums1[len1] > nums2[len2]){
 a = nums1[len1];
 len1--;
}else{
a = nums1[len1];
len2--;
}

and this one. They are totally different between each other.

if(nums1[len1] > nums2[len2]){
 a = nums1[len1]; 
}else{
a = nums1[len1];
}
len1--;
len2--;