Submission #979087

#	Time	Username	Problem	Language	Result	Execution time	Memory
979087		peterandvoi	Xylophone (JOI18_xylophone)	C++17	100 / 100	141 ms	1520 KiB

xylophone

#include <bits/stdc++.h>

#include "xylophone.h"

using namespace std;

#ifdef ngu
#include "debug.h"
#else
#define debug(...) 42
#endif

void solve(int N) {
    vector<int> res, t(N), pos(N + 1), delta(N), dist(N + 1);
    res = {1, 2};
    pos[1] = 0;
    pos[2] = 1;
    t[0] = query(1, 2);
    auto get = [&](int l, int r) {
        if (l == r) {
            return 0;
        }
        if (l > r) {
            swap(l, r);
        }
        return t[r - 1] - (l == 0 ? 0 : t[l - 1]);
    };
    auto Right = [&](int u, int delta) {
        int ans = -1;
        for (int i = u; i < int(res.size()); ++i) {
            if (get(u, i) > delta) {
                break;
            }
            ans = i + 1;
        }
        return ans;
    };
    auto Left = [&](int u, int delta) {
        int ans = -1;
        for (int i = u; i >= 0; --i) {
            if (get(u, i) > delta) {
                break;
            }
            ans = i;
        }
        return ans;
    };
    for (int i = 3; i <= N; ++i) {
        int a = pos[i - 2], b = pos[i - 1];
        for (int j = 1; j < i; ++j) {
            dist[j] = get(b, pos[j]);
        }
        int j = -1;
        int AB = dist[i - 2], BC = query(i - 1, i), AC = query(i - 2, i);
        dist[i] = BC;
        if (a < b) {
            if (AB + BC == AC) {
                j = Right(b, BC);
            } else {
                j = Left(b, BC);
            }
        } else {
            if (AB + BC == AC) {
                j = Left(b, BC);
            } else {
                j = Right(b, BC);
            }
        }
        assert(j != -1);
        res.insert(res.begin() + j, i);
        auto reset = [&]() {
            for (int i = 0; i < int(res.size()); ++i) {
                pos[res[i]] = i;
            }
            for (int i = 0; i + 1 < int(res.size()); ++i) {
                t[i] = abs(dist[res[i]] - dist[res[i + 1]]);
                if (i > 0) {
                    t[i] += t[i - 1];
                }
            }
        };
        reset();
    }
    assert(int(res.size()) == N);
    if (res[0] > res.back()) {
        reverse(res.begin(), res.end());
    }
    for (int i = 0; i < N; ++i) {
        answer(res[i], i + 1);
    }
}

• Subtask 1: 11 / 11
• Subtask 2: 36 / 36
• Subtask 3: 53 / 53