Family reunion

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
 
using namespace std;
using namespace __gnu_pbds;
 
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define fbo find_by_order
#define ook order_of_key
 
typedef long long ll;
typedef pair<ll,ll> ii;
typedef vector<int> vi;
typedef long double ld; 
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> pbds;
typedef set<int>::iterator sit;
typedef map<int,int>::iterator mit;
typedef vector<int>::iterator vit;
 
int a[1001][18];
char z[3] = {'A','B','C'};
bool used[1001];
int main()
{
	ios_base::sync_with_stdio(0); cin.tie(0);
	int n,m,k; cin>>n>>m>>k;
	for(int j = 0; j < m; j++)
	{
		for(int i = 0; i < 2*k + 1; i++)
		{
			cin>>a[j][i];
		}
	}
	if(m==1)
	{
		for(int i = 0; i < m; i++)
		{
			vi vec(2*k+2);
			for(int j = 0; j < 2*k + 1; j++)
			{
				used[a[i][j]]=1;
				vec[j]=a[i][j];
			}
			for(int j = 1; j <= n; j++)
			{
				if(!used[j]) vec[2*k+1] = j;
			}
			int dist = 0;
			int ptr = k;
			while(vec[ptr]!=1)
			{
				ptr++;
				dist++;
				if(ptr>=2*k+2) ptr=0;
			}
			cout<<z[dist%3]<<'\n';
		}
		return 0;
	}
	
}

Test 1

Group: 1

Verdict: UNKNOWN

Test 2

Group: 2

Verdict: UNKNOWN

Test 3

Group: 3

Verdict: UNKNOWN