Submission #302970

#	Time	Username	Problem	Language	Result	Execution time	Memory
302970		iliccmarko	Xylophone (JOI18_xylophone)	C++14	100 / 100	68 ms	680 KiB

xylophone

#include "xylophone.h"
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define endl "\n"

using namespace std;

int used[5005];
int a[5005];

void solve(int n)
{
    int l = 1;
    int r = n - 1;
    int start;
    while(l<=r)
    {
        int mid = (l+r)/2;
        if(query(mid, n)==n-1)
        {
            start = mid;
            l = mid + 1;
        }
        else
        {
            r = mid - 1;
        }
    }
    if(start-1>0)
    {
        a[start-1] = 1 + query(start-1, start);
        used[a[start-1]] = 1;
    }
    a[start+1] = 1 + query(start, start+1);
    used[a[start+1]] = 1;
    a[start] = 1;
    used[1] = 1;
    for(int i = start-2;i>0;i--)
    {
        int s = query(i, i+1);
        int m1 = a[i+1] + s;
        int m2 = a[i+1] - s;
        if(m1>=n||used[m1])
        {
            a[i] = m2;
            used[m2] = 1;
        }
        else if(m2<=0||used[m2])
        {
            a[i] = m1;
            used[m1] = 1;
        }
        else
        {
            int ss = query(i, i+2);
            if(max({m1, a[i+1], a[i+2]}) - min({m1, a[i+1], a[i+2]}) == ss)
            {
                a[i] = m1;
                used[m1] = 1;
            }
            else
            {
                a[i] = m2;
                used[m2] = 1;
            }
        }
    }
    for(int i = start+2;i<=n;i++)
    {
        int s = query(i-1, i);
        int m1 = a[i-1] + s;
        int m2 = a[i-1] - s;
        if(m1>n||used[m1])
        {
            a[i] = m2;
            used[m2] = 1;
        }
        else if(m2<=1||used[m2])
        {
            a[i] = m1;
            used[m1] = 1;
        }
        else
        {
            int ss = query(i-2, i);
            if(max({m1, a[i-1], a[i-2]}) - min({m1, a[i-1], a[i-2]}) == ss)
            {
                a[i] = m1;
                used[m1] = 1;
            }
            else
            {
                a[i] = m2;
                used[m2] = 1;
            }
        }
    }
    for(int i = 1;i<=n;i++)
    {
        answer(i, a[i]);
    }
}

Compilation message (stderr)

xylophone.cpp: In function 'void solve(int)':
xylophone.cpp:37:14: warning: 'start' may be used uninitialized in this function [-Wmaybe-uninitialized]
   37 |     a[start] = 1;
      |     ~~~~~~~~~^~~

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