Submission #855985

#	Time	Username	Problem	Language	Result	Execution time	Memory
855985		Cyanmond	Sure Bet (CEOI17_sure)	C++17	60 / 100	38 ms	2804 KiB

sure

#include <bits/stdc++.h>

using namespace std;

#define rep(i, l, r) for (int i = (l); i < (r); ++i)
#define per(i, l, r) for (int i = (r - 1); i >= l; --i)
#define ALL(x) (x).begin(), (x).end()

using i64 = long long;

i64 parse() {
    i64 ret = 0;
    string s;
    cin >> s;
    if (find(ALL(s), '.') == s.end()) s.push_back('.');
    while (s.end() - find(ALL(s), '.') <= 4) s += '0';
    for (const auto e : s) {
        if (std::isdigit(e)) {
            ret = 10 * ret + (e - '0');
        } else {
            continue;
        }
    }
    return ret;
}

void out(i64 v) {
    cout << v / 10000 << '.';
    i64 m = v % 10000;
    string s = to_string(m);
    while (s.size() < 4) s += '0';
    cout << s;
    cout << endl;
}

void main_() {
    int N;
    cin >> N;
    vector<i64> A(N), B(N);
    rep(i, 0, N) {
        A[i] = parse();
        B[i] = parse();
    }
    sort(ALL(A), greater());
    sort(ALL(B), greater());
    vector<i64> C(N + 1);
    rep(i, 0, N) C[i + 1] = C[i] + B[i];

    i64 sum = 0;
    constexpr i64 X = 10000;
    i64 ans = 0;
    rep(i, 0, N + 1) {
        auto eval = [&](int j) {
            i64 a = sum - (i + j) * X;
            i64 b = C[j] - (i + j) * X;
            return min(a, b);
        };

        int ok = -1, ng = N;
        while (ng - ok > 1) {
            const auto m = (ok + ng) / 2;
            i64 x = eval(m), y = eval(m + 1);
            if (x < y) ok = m;
            else ng = m;
        }
        ans = max(ans, eval(ok + 1));
        if (i == N) break;
        sum += A[i];
    }
    out(ans);
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    main_();
}

• Subtask 1: 20 / 20
• Subtask 2: 40 / 40
• Subtask 3: 0 / 40