Submission #581860

#	Time	Username	Problem	Language	Result	Execution time	Memory
581860		YaserFaisal	Xylophone (JOI18_xylophone)	C++14	100 / 100	112 ms	98700 KiB

xylophone

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

static int A[5000];

void solve(int n)
{
    int ans[5001] , pre_query[5001][5001] , found[100001] ;
    int one = 1 ;
    // searching for the one 
    int l = 1 , r = n-1 ;
    while(l<=r)
    {
        int m = (l+r)/2 ;
        pre_query[m][n] = query(m,n) ;
        if ( pre_query[m][n] == n-1  ) l = m+1 ;
        else r = m-1 ;
    }
    one = r ; 
    ans[one] = 1 ; 
    found[1] = 1 ;
    //==================================
    for ( int i = one+1 ; i <= n ; i++ )
    {
        int x , y ;
        x = pre_query[i-1][i] = query(i-1,i) ;
        if ( ans[i-1]+x > n || found[ans[i-1]+x] == 1 ) ans[i] = ans[i-1]-x ;
        else if ( ans[i-1]-x <= 1 || found[ans[i-1]-x] == 1 ) ans[i] = ans[i-1]+x ;
        else
        {
            y = pre_query[i-2][i] = query(i-2,i) ;
            if ( ans[i-1] > ans[i-2] )
            {
                if ( y == pre_query[i-2][i-1] || y == x ) ans[i] = ans[i-1]-x ;
                else ans[i] = ans[i-1]+x ;
            }
            else
            {
                if ( y == pre_query[i-2][i-1] || y == x ) ans[i] = ans[i-1]+x ;
                else ans[i] = ans[i-1]-x ;
            }
        }
        found[ans[i]] = 1 ;
    }
    //========================
    for ( int i = one-1 ; i >= 1 ; i-- )
    {
        int x , y ;
        x = pre_query[i][i+1] = query(i,i+1) ;
        if ( ans[i+1]+x > n || found[ans[i+1]+x] == 1 ) ans[i] = ans[i+1]-x ;
        else if ( ans[i+1]-x <= 1 || found[ans[i+1]-x] == 1 ) ans[i] = ans[i+1]+x ;
        else
        {
            y = pre_query[i][i+2] = query(i,i+2) ;
            if ( ans[i+1] > ans[i+2] )
            {
                if ( y == pre_query[i+1][i+2] || y == x ) ans[i] = ans[i+1]-x ;
                else ans[i] = ans[i+1]+x ;
            }
            else
            {
                if ( y == pre_query[i+1][i+2] || y == x ) ans[i] = ans[i+1]+x ;
                else ans[i] = ans[i+1]-x ;
            }
        }
        found[ans[i]] = 1 ;
    }
    //========================
    for ( int i = 1 ; i <= n ; i++ ) answer(i,ans[i]) ;
}
//query(s,t) , return abs(A[s]-A[t]) 
// answer(i,a) , A[i] = a 

Compilation message (stderr)

xylophone.cpp:5:12: warning: 'A' defined but not used [-Wunused-variable]
    5 | static int A[5000];
      |            ^

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