Submission #336389

#	Time	Username	Problem	Language	Result	Execution time	Memory
336389		KoD	Remittance (JOI19_remittance)	C++17	100 / 100	690 ms	60012 KiB

remittance

#include <bits/stdc++.h>

using i32 = std::int32_t;
using i64 = std::int64_t;
using u32 = std::uint32_t;
using u64 = std::uint64_t;
using isize = std::ptrdiff_t;
using usize = std::size_t;

template <class T>
using Vec = std::vector<T>;

constexpr i32 inf32 = (u32) ~0 >> 2;
constexpr i64 inf64 = (u64) ~0 >> 2;

int main() {
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(nullptr);
    usize N;
    std::cin >> N;
    Vec<i64> A(N), B(N);
    for (usize i = 0; i < N; ++i) {
        std::cin >> A[i] >> B[i];
    }
    Vec<i64> dif(N);
    for (usize i = 0; i < N; ++i) {
        const auto j = (i + 1 == N ? 0 : i + 1);
        dif[i] = B[j] - A[j];
    }
    std::vector<i64> number(N + 30);
    const auto add = [&](std::vector<i64> &vec, i64 x, const usize shift) {
        bool neg = (x < 0);
        x = std::abs(x);
        for (usize d = 0; d < 30; ++d) {
            if (x >> d & 1) {
                vec[shift + d] += (neg ? -1 : 1);
            }
        }
    };
    const auto fix = [&](std::vector<i64> &vec) {
        for (usize i = 0; i + 1 < vec.size(); ++i) {
            if (vec[i] < 0) {
                const auto tmp = -vec[i];
                vec[i] += tmp * 2;
                vec[i + 1] -= tmp;
            }
            const auto tmp = vec[i] / 2;
            vec[i] -= tmp * 2;
            vec[i + 1] += tmp;
        }
    };
    add(number, -dif[N - 1], 0);
    for (usize i = 0; i + 1 < N; ++i) {
        add(number, -dif[i], i + 1);
    }
    fix(number);
    if (number.back() < 0) {
        std::cout << "No\n";
        return 0;
    }
    i64 big = 1000000000, small = -1;
    while (big - small > 1) {
        const auto md = (big + small) / 2;
        std::vector<i64> comp(number.size());
        add(comp, md, N);
        add(comp, -md, 0);
        fix(comp);
        bool large = true;
        for (usize i = number.size(); i --> 0;) {
            if (comp[i] < number[i]) {
                large = false;
                break;
            }
            if (comp[i] > number[i]) {
                break;
            }
        }
        (large ? big : small) = md;
    }
    Vec<i64> X(N);
    X[N - 1] = big;
    for (usize i = N - 1; i --> 0;) {
        X[i] = dif[i] + 2 * X[i + 1];
        if (X[i] < 0) {
            std::cout << "No\n";
            return 0;
        }
    }
    for (usize step = 0; step < 30; ++step) {
        for (usize i = 0; i < N; ++i) {
            const auto j = (i + 1 == N ? 0 : i + 1);
            const auto tmp = std::min(X[i], A[i] / 2);
            X[i] -= tmp;
            A[i] -= 2 * tmp;
            A[j] += tmp;
        }
    }
    for (usize i = 0; i < N; ++i) {
        if (A[i] != B[i]) {
            std::cout << "No\n";
            return 0;
        }
    }
    std::cout << "Yes\n";
    return 0;
}

• Subtask 1: 15 / 15
• Subtask 2: 40 / 40
• Subtask 3: 45 / 45