Submission #918995

#	Time	Username	Problem	Language	Result	Execution time	Memory
918995		viwlesxq	Xylophone (JOI18_xylophone)	C++17	0 / 100	1 ms	592 KiB

xylophone

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

void solve(int n) {
    vector<int> a(n + 1), d(n + 1);
    for (int i = 1; i < n; ++i) {
        d[i] = query(i, i + 1);
    }
    int min = 1, hi = n;
    while (min + 1 < hi) {
        int mid = (min + hi) / 2;
        if ((mid + 1 < n ? query(mid, n) : d[mid]) == n - 1) min = mid;
        else hi = mid;
    }
    a[min] = 1;
    int last = min, sum = 0;
    bool increasing = true;
    map<int, bool> used;
    used[1] = true;
    for (int i = min - 1; i > 0; --i) {
        int add = d[i];
        if (used[a[i + 1] + add] || a[i + 1] - add > n) {
            if (increasing) increasing = false, sum = 0;
        } else if (used[a[i + 1] - add] || a[i + 1] + add <= 0) {
            if (!increasing) increasing = true, sum = 0;
        } else {
            int diff = (i + 1 < last ? query(i, last) : d[i]);
            if (sum + add != diff) {
                last = i + 1, sum = 0;
                increasing ^= true;
            }
        }
        a[i] = a[i + 1] + (increasing ? add : -add);
        used[a[i]] = true;
        sum += add;
    }
    last = min, sum = 0;
    increasing = true;
    for (int i = min + 1; i <= n; ++i) {
        int add = d[i - 1];
        if (used[a[i - 1] + add] || a[i - 1] - add > n) {
            if (increasing) increasing = false, sum = 0;
        } else if (used[a[i - 1] - add] || a[i - 1] + add <= 0) {
            if (!increasing) increasing = true, sum = 0;
        } else {
            int diff = (last + 1 < i ? query(last, i) : d[last]);
            if (sum + add != diff) {
                last = i - 1, sum = 0;
                increasing ^= true;
            }
        }
        a[i] = a[i - 1] + (increasing ? add : -add);
        used[a[i]] = true;
        sum += add;
    }
    for (int i = 1; i <= n; ++i) {
        answer(i, a[i]);
    }
}

• Subtask 1: 0 / 11
• Subtask 2: 0 / 36
• Subtask 3: 0 / 53