Submission #890987

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Source Code Expand

#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <algorithm>
#include <cstring>
#include <cmath>
#define REP(i,n) for (int i=1;i<=(n);++i)
#define FOR(i,a,b) for (int i=(a);i<=(b);++i)
#define ROF(i,a,b) for (int i=(a);i>=(b);--i)
#define FEC(p,u) for (edge*p=head[u];p;p=p->nxt)
using namespace std;
typedef long long LL;

int n, a[110000], ans;
int main(){
	scanf("%d", &n);
	REP(i,n) scanf("%d", a+i);
	REP(i,n) if (a[a[i]] == i) ++ans;
	printf("%d\n", ans/2);
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:16:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &n);
                 ^
./Main.cpp:17:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  REP(i,n) scanf("%d", a+i);
                           ^

Judge Result