출처 : https://leetcode.com/problems/merge-sorted-array/
class Solution {
public void merge(int[] nums1, int m, int[] nums2, int n) {
int A = m - 1;
int B = n - 1;
int C = m + n - 1;
while (A >= 0 && B >= 0)
nums1[C--] = (nums1[A] > nums2[B]) ? nums1[A--] : nums2[B--];
while(B>=0)
nums1[C--] = nums2[B--];
}
}