Submission #8897826

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Source Code Expand

#include <bits/stdc++.h>
#define ls (o << 1)
#define rs (o << 1 | 1)
#define mid ((L + R) >> 1)
using namespace std;
typedef long long LL;
const int N = 100500;
const int mod = 1e9 + 7;
int a[N], b[N], n;
int main() {
#ifdef TEST
	freopen("input.txt", "r", stdin);
#endif
	scanf("%d", &n);
	for (int i = 0; i < n; ++i) {
		scanf("%d", &a[i]);
	}
	sort(a, a + n);
	int m = 1;
	b[m - 1] = 1;
	for (int i = 1; i < n; ++i) {
		if (a[i] != a[i - 1]) {
			if (b[m - 1] == 1) {
				a[m - 1] = a[i];
				b[m - 1] = 0;
			} else {
				a[m++] = a[i];
			}
		}
		b[m - 1]++;
	}
	if (b[m - 1] == 1) m--;
	long long ans = 0;
	for (int i = m - 1; i >= 0; --i) {
		if (b[i] > 4) {
			ans = max(ans, 1LL * a[i] * a[i]);
		}
	}
	if (m > 1) {
		ans = max(ans, 1LL * a[m - 1] * a[m - 2]);
	}
	cout << ans << endl;
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:14:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &n);
                 ^
./Main.cpp:16:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &a[i]);
                     ^

Judge Result