2022-06-07 Daily-Challenge

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In: DailyChallenge

Today I have done leetcode's June LeetCoding Challenge with cpp.

June LeetCoding Challenge 7

Description

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.

Constraints:

  • nums1.length == m + n
  • nums2.length == n
  • 0 <= m, n <= 200
  • 1 <= m + n <= 200
  • -10^9 <= nums1[i], nums2[j] <= 10^9

Follow up: Can you come up with an algorithm that runs in O(m + n) time?

Solution

class Solution {
public:
  void merge(vector<int>& nums1, int m, vector<int>& nums2, int n) {
    while(m && n) {
      if(nums1[m-1] > nums2[n-1]) {
        nums1[m+n-1] = nums1[m-1];
        m -= 1;
      } else {
        nums1[m+n-1] = nums2[n-1];
        n -= 1;
      }
    }
    while(n) {
      nums1[n-1] = nums2[n-1];
      n -= 1;   
    }
  }
};

// Accepted
// 59/59 cases passed (0 ms)
// Your runtime beats 100 % of cpp submissions
// Your memory usage beats 72.57 % of cpp submissions (9.1 MB)
Algorithm