88. Merge Sorted Array [Leetcode][C++]

class Solution { public: void merge(vector<int>& nums1, int m, vector<int>& nums2, int n) { // Brute force approach Time O(NlogN) & Auxiliary Space O(1) // Just overwrite nums2 on nums1 starting  // from the point where non zero element ends in nums1  for(int i=m;i<m+n;i++){ nums1[i]=nums2[i-m]; } // Sort function has O(NlogN) time complexity sort(nums1.begin(),nums1.end()); } }; 

class Solution { public: void merge(vector<int>& nums1, int m, vector<int>& nums2, int n) { // Optimal Solution Time O(N) & Auxiliary Space O(1) // Two pointer approach  int p1 = m - 1, p2 = n - 1, curr=m+n-1; for (int i = curr; i >= 0 && p2 >=0 ;i--) { if (p1 >= 0 && nums1[p1] > nums2[p2]) nums1[i] = nums1[p1--]; else nums1[i] = nums2[p2--]; } } };