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Remove Duplicates from Sorted Array — LeetCode

Photo by Roman Synkevych on Unsplash
  • 0 <= nums.length <= 3 * 104
  • -100 <= nums[i] <= 100
  • nums is sorted in non-decreasing order
int[] nums = [...]; // Input array
int[] expectedNums = [...]; // The expected answer with correct length
int k = removeDuplicates(nums); // Calls your implementationassert k == expectedNums.length;
for (int i = 0; i < k; i++) {
assert nums[i] == expectedNums[i];

My Solution —

class solution {
int removeDuplicates(vector<int>& nums)//given parameter's vector
unordered_set<int> s; // taken a set as a variable
for(int i:nums) // mapped through all the elements of nums
s.insert(i); //inserted the non duplicate elements in s
nums.clear() // emptied the vector nums
for(int i:s)
nums.push_back(i) //appended the elements from s to nums
sort(nums.begin(), nums.end()) //sorted nums
return s.size()

Runtime: 20 ms

Memory Usage: 18.9 MB

Other Solution —

class Solution { 
int removeDuplicates(vector<int>& nums)
int j = 0;
int n = nums.size();
if(n <= 1) return n; //return the size of nums if n<=1
for(int i = 1; i<n; i++)
if(nums[i] != nums[j])
nums[j] = nums[i]; //
return j+1;

Runtime: 16 ms

Memory Usage: 18.2 MB



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Arash Arora

Hey! I'm Arash Arora, currently pursuing my Btech in CSE with cybersecurity as a specialization.