Submission #630117

#	Time	Username	Problem	Language	Result	Execution time	Memory
630117		Neos	Hacker (BOI15_hac)	C++14	100 / 100	326 ms	20300 KiB

hac

#include <bits/stdc++.h>
using namespace std;

using ll = long long;
using ld = long double;
using ull = unsigned long long;
using ii = pair<ll, ll>;

#define fastIO ios::sync_with_stdio(0); cin.tie(0);
#define fi first
#define se second
#define pb push_back
#define numBit(x) (__builtin_popcountll(1ll * (x)))
#define getBit(x, i) ((x) >> (i) & 1)
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define MASK(x) (1ll << (x))

template<class X, class Y>
    bool minimize(X &x, const Y &y) {
        X eps = 1e-9;
        if (x > y + eps) {
            x = y;
            return true;
        } else return false;
    }
template<class X, class Y>
    bool maximize(X &x, const Y &y) {
        X eps = 1e-9;
        if (x + eps < y) {
            x = y;
            return true;
        } else return false;
    }

const int N = 1e6 + 7, oo = 1e9 + 7;

int n, a[N];

signed main() {
    fastIO;
    if (fopen("test.inp", "r")) {
        freopen("test.inp", "r", stdin);
        freopen("test.out", "w", stdout);
    }
    cin >> n;
    for (int i = 1; i <= n; i++) cin >> a[i], a[i + n] = a[i];
    for (int i = 1; i <= 2 * n; i++) a[i] += a[i - 1];

    vector<int> ret(n + 1, oo);
    multiset<int> val; int len = n + 1 >> 1;
    for (int i = 1; i <= 2 * n; i++) {
        if (i + len - 1 <= 2 * n) val.insert(a[i + len - 1] - a[i - 1]);
        if (i > len) val.erase(val.find(a[i - 1] - a[i - 1 - len]));

        int prv = (i - 1) % n + 1;
        minimize(ret[prv], *val.begin());
    }

    int ans = 0;
    for (int i = 1; i <= n; i++) maximize(ans, ret[i]);
    cout << ans;
}

Compilation message (stderr)

hac.cpp: In function 'int main()':
hac.cpp:51:36: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   51 |     multiset<int> val; int len = n + 1 >> 1;
      |                                  ~~^~~
hac.cpp:43:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   43 |         freopen("test.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
hac.cpp:44:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 |         freopen("test.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 20 / 20
• Subtask 4: 40 / 40