Submission #363243

#	Time	Username	Problem	Language	Result	Execution time	Memory
363243		buyolitsez	Xylophone (JOI18_xylophone)	C++17	100 / 100	124 ms	768 KiB

xylophone

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

using namespace std;

bool Check(int a, int b, int c, int i) {
    if (a == b || b == c || a == c) {return false;}
    if (a > b && b > c) {
        return query(i + 1, i + 3) == a - c;
    }
    if (a > c && c > b) {
        return query(i + 1, i + 3) == a - b;
    }
    if (c > a && a > b) {
        return query(i + 1, i + 3) == c - b;
    }
    if (c > b && b > a) {
        return query(i + 1, i + 3) == c - a;
    }
    if (b > a && a > c) {
        return query(i + 1, i + 3) == b - c;
    }
    if (b > c && c > a) {
        return query(i + 1, i + 3) == b - a;
    }
}

int GetRight(int n, int a, int b, int x, int i) {
    int c1 = b + x, c2 = b - x;
    if (c1 > n) {return c2;}
    if (c2 < 1) {return c1;}
    if (Check(a, b, c1, i)) {
        return c1;
    }
    return c2;
}

int GetLeft(int n, int a, int b, int x, int i) {
    int c1 = a + x, c2 = a - x;
    if (c1 > n) {return c2;}
    if (c2 < 1) {return c1;}
    if (Check(c1, a, b, i)) {
        return c1;
    }
    return c2;
}


void solve(int n) {
    int pos = n - 1;
    int l = 0, r = n;
    while (r - l > 1) {
        int m = l + (r - l) / 2;
        if (query(1, m) == n - 1) {
            r = m;
        } else {
            l = m;
        }
    }
    pos = l;
    vector <int> num(n);
    num[pos] = n;
    if (pos + 1 < n) {
        int x = query(pos + 1, pos + 2);
        num[pos + 1] = n - x;
    }
    vector <vector<int>> cand1(n), cand2(n);
    for (int i = pos + 2; i < n; ++i) {
        int x = query(i, i + 1);
        num[i] = GetRight(n, num[i - 2], num[i - 1], x, i - 2);
    }
    if (pos != 0) {
        int x = query(pos, pos + 1);
        num[pos - 1] = n - x;
    }
    for (int i = pos - 2; i >= 0; --i) {
        int x = query(i + 1, i + 2);
        num[i] = GetLeft(n, num[i + 1], num[i + 2], x, i);
    }
    for(int i = 0; i < n; ++i) {
        answer(i + 1, num[i]);
    }
}

Compilation message (stderr)

xylophone.cpp: In function 'bool Check(int, int, int, int)':
xylophone.cpp:26:1: warning: control reaches end of non-void function [-Wreturn-type]
   26 | }
      | ^

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