Getting WA for CATFEED

Getting WA for my code, help me out where have i gone wrong?
https://www.codechef.com/LTIME76B/problems/CATFEED

#include<bits/stdc++.h>
using namespace std;

int main()
{
#ifndef ONLINE_JUDGE
freopen(“input.txt”, “r”, stdin);
freopen(“output.txt”, “w”, stdout);
#endif

int t;
cin >> t;
while(t--){
	int n, m;
	cin >> n >> m;

	int ar[m+1];
	for(int i=1; i<=m; i++)
		cin >> ar[i];


	bool flag = true;
	// Divivde these operation in terms of 'N'
	int i, k;
	for(i=1, k=1; i<=m; i++){
		if(i%n == 0){
			// sort every n size block and
			// check if all the elemement are distinct
			sort(ar+k, ar+i+1);

			for(int l=k; l<=i-1; l++){
				if(ar[l]!=ar[l+1]){
					flag = true;
				}
				else{
					flag = false;
					break;
				}
			}
			k = i+1;
		}
	}

	// cout <<" K : " << k << endl;
	// Left over check
	if(k<m && flag!=false){
		sort(ar+k, ar+m+1);
		for(int x=k; x<=m; x++){
			//cout << ar[x] << " ";
			if(ar[x]!=ar[x+1]){
				flag = true;
			}
			else{
				flag = false;
				break;
			}
		}
		//cout << endl;
	}

	cout << (flag ? "YES\n" : "NO\n");
}
return 0;

}