Merge Sorted Array

LeetCode #88

Description:

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.

Example:

Note

Idea:

需要in place。

Work on nums1, go from back to front.

Code:

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

        while(ia>=0 && ib>=0){
            if(nums1[ia]<=nums2[ib]){
                nums1[icurr--]=nums2[ib--];
            }
            else{
                nums1[icurr--]=nums1[ia--];
            }
        }

        while(ib>=0){
            nums1[icurr--]=nums2[ib--];
        }

    }
};