Submission #774063

#	Time	Username	Problem	Language	Result	Execution time	Memory
774063		Dan4Life	Xylophone (JOI18_xylophone)	C++17	100 / 100	58 ms	392 KiB

xylophone

#include "xylophone.h"
#include <bits/stdc++.h>
using namespace std;
 
int a[5010], _ok[20000];
int *ok = _ok+10000;
void Answer(int x, int v){
    answer(x,v); a[x]=v; ok[v]=1; 
}
 
void solve(int n) {
    int l = 1, r = n-1;
    while(l<r){
        int mid = (l+r+1)/2;
        if(query(mid,n)==n-1) l=mid;
        else r=mid-1;
    }
    for(int i = -2*n; i <= 2*n; i++) ok[i]=(i<1 or i>n);
    Answer(l,1);
    if(l!=1) Answer(l-1,query(l-1,l)+1);
    Answer(l+1,query(l,l+1)+1);
    for(int i = l-2; i>=1; i--){
        int dif = query(i,i+1);
        int x1 = a[i+1]-dif, x2 = a[i+1]+dif;
        if(ok[x1]) swap(x1,x2);
        if(ok[x2]) Answer(i,x1);
        else{
            int dif2 = query(i,i+2);
			if(max({x1,a[i+1],a[i+2]})-min({x1,a[i+1],a[i+2]})==dif2) Answer(i,x1);
            else Answer(i,x2);
        }
    }
	for(int i = l+2; i<=n; i++){
        int dif = query(i-1,i);
        int x1 = a[i-1]-dif, x2 = a[i-1]+dif;
        if(ok[x1]) swap(x1,x2);
        if(ok[x2]) Answer(i,x1);
        else{
            int dif2 = query(i-2,i);
            if(max({x1,a[i-1],a[i-2]})-min({x1,a[i-1],a[i-2]})==dif2) Answer(i,x1);
            else Answer(i,x2);
        }
    }
}

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