88. 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 and nums2 are m and n respectively.

解题思路：

从后往前比较。

class Solution {
public:
void merge(vector<int>& nums1, int m, vector<int>& nums2, int n) {
int i = m - 1;
int j = n - 1;
int k = m + n - 1;

while (k >= 0 && i >= 0 && j >= 0) {
if (nums1[i] > nums2[j])
nums1[k--] = nums1[i--];
else
nums1[k--] = nums2[j--];
}

while (i >= 0)
nums1[k--] = nums1[i--];

while (j >= 0)
nums1[k--] = nums2[j--];
}
};