88_MergedSort.cpp

#include <vector>
#include <algorithm>
#include <iostream>

void printVector(std::vector<int> numVec);

/*
88. Merge Sorted Array
You are given two integer arrays nums1 and nums2,
sorted in non-decreasing order, and two integers m and n,
representing the number of elements in nums1 and nums2 respectively.

Merge nums1 and nums2 into a single array sorted in non-decreasing order.

The final sorted array should not be returned by the function,
but instead be stored inside the array nums1.

To accommodate this, nums1 has a length of m + n,
where the first m elements denote the elements that should be merged,
and the last n elements are set to 0 and should be ignored. nums2 has a length of n.



Example 1:
Input: nums1 = [1,2,3,0,0,0], m = 3, nums2 = [2,5,6], n = 3
Output: [1,2,2,3,5,6]
Explanation: The arrays we are merging are [1,2,3] and [2,5,6].
The result of the merge is [1,2,2,3,5,6] with the underlined elements coming from nums1.


Example 2:
Input: nums1 = [1], m = 1, nums2 = [], n = 0
Output: [1]
Explanation: The arrays we are merging are [1] and [].
The result of the merge is [1].

Example 3:
Input: nums1 = [0], m = 0, nums2 = [1], n = 1
Output: [1]
Explanation: The arrays we are merging are [] and [1].
The result of the merge is [1].
Note that because m = 0, there are no elements in nums1. The 0 is only there to ensure the merge result can fit in nums1.

*/

class Solution
{
public:
    void merge(std::vector<int> &nums1, int m, std::vector<int> &nums2, int n)
    {
        // remove trailing zeros from nums1
        while (!nums1.empty() && nums1[nums1.size() - 1] == 0)
        {
            nums1.pop_back();
            if (nums1.size() == m)
            {
                break;
            }
        }

        // append nums2 to nums1
        nums1.insert(nums1.end(), nums2.begin(), nums2.end());

        // sort nums1.
        std::sort(nums1.begin(), nums1.end());
    }
};

int main()
{
    Solution S1;
    std::vector<int> nums1 = {1, 2, 3, 0, 0, 0};
    int m = 3;
    std::vector<int> nums2 = {2, 5, 6};
    int n = 3;

    std::cout
        << "nums1: ";
    printVector(nums1);
    std::cout
        << "m: " << m << "\n";

    std::cout
        << "nums2: ";
    printVector(nums2);
    std::cout
        << "n: " << n << "\n";

    S1.merge(nums1, m, nums2, n);

    printVector(nums1);
}