Submission #815373

#	Time	Username	Problem	Language	Result	Execution time	Memory
815373		Pikachu	Xylophone (JOI18_xylophone)	C++17	100 / 100	64 ms	440 KiB

xylophone

#include <bits/stdc++.h>
#include "xylophone.h"

using namespace std;

const int maxn = 5010;
int a[maxn];
bool done[maxn];

void solve(int n) 
{
    int l = 1;
    int r = n;
    int dak = 1;
    while (l <= r) {
        int mid = (l + r) / 2;
        if (query(mid, n) == n - 1) dak = mid, l = mid + 1;
        else r = mid - 1;
    }
    l = dak;
    answer(l, 1);
    a[l] = 1;
    done[1] = true;
    for (int i = l - 1; i >= 1; i--) {
        int x = query(i, i + 1);
        int ans = -1;
        if (a[i + 1] - x <= 0 || done[a[i + 1] - x]) ans = a[i + 1] + x;
        if (a[i + 1] + x > n || done[a[i + 1] + x]) ans = a[i + 1] - x;
        if (ans == -1) {
            if (max({a[i + 1] + x, a[i + 1], a[i + 2]})
              - min({a[i + 1] + x, a[i + 1], a[i + 2]})
             != query(i, i + 2)) ans = a[i + 1] - x;
            else ans = a[i + 1] + x;
        }
        a[i] = ans;
        done[ans] = true;
        answer(i, a[i]);
    }
    for (int i = l + 1; i <= n; i++) {
        int x = query(i - 1, i);
        int ans = -1;
        if (a[i - 1] - x <= 0 || done[a[i - 1] - x]) ans = a[i - 1] + x;
        if (a[i - 1] + x > n || done[a[i - 1] + x]) ans = a[i - 1] - x;
        if (ans == -1) {
            if (max({a[i - 1] + x, a[i - 1], a[i - 2]})
              - min({a[i - 1] + x, a[i - 1], a[i - 2]})
             != query(i - 2, i)) ans = a[i - 1] - x;
            else ans = a[i - 1] + x;
        }
        a[i] = ans;
        done[ans] = true;
        answer(i, a[i]);
    }
}

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