9466.cpp

#include <stdio.h>
int nt[100005], team[100005], n;
int start, dap;
void visit(int v){
    int next = nt[v];
    team[v] = -start;
    if( team[next] == 0 ){
      visit(next);
      if( team[next] == 1 && dap > 0 ){
        team[v] = 1;
      }
    }
    else if( team[next] == -start ){
      dap = next;
      team[v] = 1;
    }

    if( dap == v ){
      dap = 0;
    }
}

int main(int argc, char const *argv[]) {
  int test_case;
  scanf("%d", &test_case);
  for( int test = 0; test < test_case; test ++ ){
    scanf("%d", &n);
    for( int i = 1 ; i <= n ; i ++ ){
      scanf("%d", &nt[i]);
    }

    for( int i = 1 ; i <= n ; i ++ ){
      if( team[i] == 0 ){
        start = i; dap = 0;
        visit(i);
      }
    }

    int teamcnt = 0;
    for( int i = 1 ; i <= n ; i ++ ){
      if( team[i] == 1 ){
        teamcnt++;
      }
      team[i] = 0;
    }
    printf("\n%d\n", n - teamcnt);
  }
  return 0;
}