26.txt

Remove Deuplicates from Sorted Array

Given an array in non-decreasing order you need to remove the duplicates in-place

If it was not in-place then we could take a map and keep track of count and then according to that modify the element of array
OR
We could track the count of duplicates and then use that count to keep a pointer over i-count to store the unique elements

int removeDuplicates(vector<int>& nums) {
    int count=0;
    for(int i=1;i<nums.size();i++){
        if(nums[i]==nums[i-1]){
            count++;
        }
        else{
            nums[i-count]=nums[i];
        }
    }
    return nums.size()-count;
    // OR If not in-place
    // map<int,int> mp;
    // for(auto n:nums){
    //     mp[n]++;
    // }
    // int i=0;
    // for(auto m:mp){
    //     nums[i++]=m.first;
    // }
    // return i;
}