Neet Code 150 C++

Using c++20

217. Contains Duplicate

Method	Time Complexity	Space Complexity
Unordered_set	O(n)	O(n)
Two Pointer	O(n)	O(1)

Set

int longestConsecutive(vector<int>& nums){
  std::unordered_set<int> memo(nums.begin(), nums.end());
  int res = 0;

  for(int i: memo){
    if(!memo.contains(i - 1)){
      int counter = 1;
      while(memo.contains(i + counter))
        counter += 1; 
      res = max(res, counter);
    }
  }
  return res;
}

Binary Search

int search(vector<int>& nums, int target) {
  int l = 0;
  int r = nums.size() - 1;

  while(l < r){
    int m = (r + l) / 2;

    if(nums[m] < target){
      l = m + 1;
    }
    else{
      r = m;
    }
  }

  return nums[l] == target ? l : -1;
}