88. Merge Sorted Array

Given two sorted integer arrays nums1 and nums2, merge nums2 into nums1 as one sorted array.

Note:

• The number of elements initialized in nums1 and nums2 are m and n respectively.
• You may assume that nums1 has enough space (size that is greater or equal to m + n) to hold additional elements from nums2.

Example:

Input:
nums1 = [1,2,3,0,0,0], m = 3
nums2 = [2,5,6],       n = 3

Output: [1,2,2,3,5,6]

AC code:

class Solution {
public:
    void merge(vector<int>& nums1, int m, vector<int>& nums2, int n) {
        vector<int> nums3;
        for (int i = 0; i < m; ++i)
            nums3.push_back(nums1[i]);
        for (int i = 0; i < n; ++i)
            nums3.push_back(nums2[i]);
        sort(nums3.begin(), nums3.end());
        nums1 = nums3;
    }
};

Runtime: 4 ms, faster than 99.52% of C++ online submissions for Merge Sorted Array.

AC code2:

class Solution {
public:
    void merge(int A[], int m, int B[], int n) {
        int i=m-1;
        int j=n-1;
        int k = m+n-1;
        while(i >=0 && j>=0)
        {
            if(A[i] > B[j])
                A[k--] = A[i--];
            else
                A[k--] = B[j--];
        }
        while(j>=0)
            A[k--] = B[j--];
    }
};