群的判定

#include <bits/stdc++.h>
#define ll long long
using namespace std;
int arr[110];
int vis[110];
int num[110];
int b[110];
int main()
{
    int n, m, q;
    while(cin >> n >> m >> q)
    {
        int flag = 1;
        memset(b,0,sizeof(b));
        memset(vis,0,sizeof(vis));
        memset(num,-1,sizeof(num));
        memset(arr,-1,sizeof(arr));
        for(int i = 1; i <= n; i++)
        {
            cin>>arr[i];
            vis[arr[i]] = 1;
        }
        for(int i = 1; i <= q; i++)
        {
            cin>>b[i];
        }
        if(vis[0]==0)
        {
            flag = 0;
        }
        num[0] = 0;
        for(int i = 1; i <= n; i++)
        {
            for(int j = 1; j <= n; j++)
            {
                if(vis[(arr[i] + arr[j]) % m] && (arr[i] + arr[j]) % m == 0)
                {
                    num[arr[i]] = arr[j];
                    num[arr[j]] = arr[i];
                    break;
                }
            }
        }
        for(int i = 1; i <= n; i++)
        {
            if(num[arr[i]] == -1)
            {
                flag = 0;
            }
        }
        if(!flag)
        {
            cout << "-1" << endl;
        }
        else
        {
            for(int i = 1; i <= q; i++)
            {
                cout << num[b[i]] << endl;
            }
        }
    }
    return 0;
}