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OI-codes/S2OJ/181/181.cpp

28 lines
597 B
C++

#include <iostream>
#include <algorithm>
using std::cin;
using std::cout;
#define endl '\n'
const int N = 200005;
int n, a[N], ans;
int main() {
cin >> n;
for (int i = 1; i <= n; i++) {
cin >> a[i];
}
std::sort(a + 1, a + 1 + n);
n = std::unique(a + 1, a + 1 + n) - a - 1;
a[n + 1] = std::numeric_limits<int>::max();
for (int i = 1; i <= n; i++) {
for (int j = 2; (j - 1) * a[i] <= a[n]; j++) {
ans = std::max(ans, *(std::lower_bound(a + 1, a + 1 + n + 1, j * a[i]) - 1) % a[i]);
}
}
cout << ans << endl;
return 0;
}