提出 #893173

---

ソースコード 拡げる

#include <algorithm>
#include <cstdio>
#include <vector>
#include <valarray>
#include <queue>
#include <iostream>
#include <numeric>
#define FOR(i, a, b) for(int i = (a); i < (b); ++i)
#define REP(i, n) FOR(i, 0, n)
#define rFOR(i, a, b) for(int i = (a); i >= (b); --i)
#define rREP(i, n) rFOR(i, n-1, 0)
#define AND &&
#define OR ||
#define IN(x, min, max) (min <= x AND x < max)
#define VEC(type) vector<type>
#define DVEC(type) vector<vector<type>>
#define VAL(type) valarray<type>
#define ARRAY_SIZE(array) (sizeof(array)/sizeof(array[0]))
#define HOGE printf("%s\n", "hoge");
#define DUMP(p) cout << p << endl;
const int INF = 2323232323;
using namespace std;
typedef pair<int, int> P;

int N;
int main(){
    scanf("%d", &N);
    VEC(int) a(N);
    REP(i, N){
        scanf(" %d", &a[i]);
    }
    VEC(int) dp(N, -1);
    int ans = 0;
    REP(i, N){
        if (dp[i] > 0) {
            continue;
        }
        if (i+1 == a[a[i]-1]) {
            ans++;
            dp[a[i]-1] = 1;
        }
    }
    printf("%d\n", ans);
    return 0;
}

提出情報

コンパイルエラー

./Main.cpp: In function ‘int main()’:
./Main.cpp:27:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &N);
                    ^
./Main.cpp:30:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
         scanf(" %d", &a[i]);
                            ^

ジャッジ結果