count-distinct-elements-in-every-window-of-size-k.cpp

//
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ft first
#define sc second
#define pb push_back
#define ins insert
#define all(v) v.begin(), v.end()
#define Sort(v) sort(all(v))
#define s(a, n) sort(a, a + n)
#define f1(i,a,b) for(ll i=a;i<b;i++)
#define f2(i,a,b,c) for(ll i=a;i<b;i+=c)
#define f3(i,a,b) for(ll i=a;i>=b;i--)
#define f4(i,a,b,c) for(ll i=a;i>=b;i-=c)
#define jatin(t) int t; cin >> t; while(t--)
const int N = 1e5+2, MOD = 1e9+7;
//int array[N];
//cout << (condition ? "YES\n" : "NO\n");
// { Driver Code Starts
#include <bits/stdc++.h>
using namespace std;



 // } Driver Code Ends

class Solution{
  public:
    vector <int> countDistinct (int arr[], int n, int k)
    {
        //code here.
        vector<int> v;
        map<int,int> mp;
        for(int i=0;i<k;i++){
            mp[arr[i]]++;
        }
        v.push_back(mp.size());
        for(int i=0;i<n-k;i++){
            
           
            mp[arr[i+k]]+=1;
            if(mp[arr[i]]==1)
            mp.erase(arr[i]);
            else
            mp[arr[i]]-=1;
            v.push_back(mp.size());
             
        }
        return v;
    }
};

// { Driver Code Starts.
int main()
{
    int t;
    cin >> t;
    while (t--)
    {

        int n, k;
        cin >> n >> k;
        int a[n];
        for (int i = 0; i < n; i++) 
        	cin >> a[i];
        Solution obj;
        vector <int> result = obj.countDistinct(a, n, k);
        for (int i : result) 
        	cout << i << " ";
        cout << endl;
    }
    return 0;
}  // } Driver Code Ends