SCPC-PRACTICE-ROUND1-FRIENDS.md

#include <iostream>

using namespace std;

int Answer, N;

void collect(int* arr, int* cmp, int j) {
    int i = arr[j];
    cmp[j] = 0;
    if (i+j>N) return;
    else if (cmp[i+j]==0) {
        Answer--;
        return;
    }
    else if (i<=N) {
        collect(arr, cmp, i+j);
    }
    else return;
}

int main(int argc, char** argv)
{
	int T, test_case;
    setbuf(stdout, NULL);
	
	cin >> T;
	for(test_case = 0; test_case  < T; test_case++)
	{

		Answer = 0;
		/////////////////////////////////////////////////////////////////////////////////////////////
        cin >> N;
        int *arr = new int[N+1];
        int *cmp = new int[N+1];
        arr[0] = 0; cmp[0] = 0;
        for (int i=1; i<=N; i++) {
            int num;
            cin >> num;
            if (num<=0 || num>N) return 0;
            else {
                arr[i] = num;
                cmp[i] = num;
            }
        }

        for (int i=1; i<=N; i++) {
            if (cmp[i]==0) continue;
            else {
                collect(arr, cmp, i);
                Answer++;
            }
        }
		/////////////////////////////////////////////////////////////////////////////////////////////
		
		// Print the answer to standard output(screen).
		cout << "Case #" << test_case+1 << endl;
		cout << Answer << endl;
        delete[] arr;
        delete[] cmp;
	}

	return 0;//Your program should return 0 on normal termination.
}