leetcode | Merge Sorted Array

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 nums1

将两个数组合并到其中一个数组中，从后往前遍历。
将两个数组合并到另一个缓存数组中，一般从前向后遍历

//时间复杂度O(m+n), 空间复杂度O(1)
void merge(int* nums1, int m, int* nums2, int n) {
    int i = m-1, j = n-1, k = m+n-1;
    while (j >= 0) {
        if (i >= 0)
            nums1[k--] = (nums1[i] > nums2[j]) ? nums1[i--] : nums2[j--];
        else
            nums1[k--] = nums2[j--];
    }    
    return;
}