Submission #1293047

#	Time	Username	Problem	Language	Result	Execution time	Memory
1293047		trandangquang	Xylophone (JOI18_xylophone)	C++20	100 / 100	32 ms	440 KiB

xylophone

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

#define foru(i,a,b) for(int i=(a); i<=(b); ++i)
#define ford(i,a,b) for(int i=(a); i>=(b); --i)
#define rep(i,a) for(int i=0; i<(a); ++i)
#define sz(a) (int)(a).size()
#define all(a) (a).begin(),(a).end()
#define bit(s,i) (((s)>>(i))&1)
#define ii pair<int,int>
#define fi first
#define se second
#define pb push_back
#define eb emplace_back
#define ll long long
#define _ << " " <<

template <class X, class Y> bool maxi(X &x, Y y){return x<y?x=y,true:false;}
template <class X, class Y> bool mini(X &x, Y y){return x>y?x=y,true:false;}

const int MAXN=5050;

int n,d2[MAXN],d3[MAXN],isSame[MAXN],p[MAXN];

void solve(int N){
    n=N;
    foru(i,1,n-1){
        d2[i]=query(i,i+1);
    }
    foru(i,1,n-2){
        d3[i]=query(i,i+2);
    }
    foru(i,2,n-1){
        if(d2[i-1]+d2[i]==d3[i-1]) isSame[i]=1;
        else isSame[i]=0;
    }

    /// initially, sign=-1
    int sign=-1;
    p[1]=0; p[2]=sign*d2[1];
    foru(i,2,n-1){
        if(!isSame[i]) sign*=-1;
        p[i+1]=p[i]+sign*d2[i];
    }

    int mi=0;
    foru(i,1,n) mini(mi,p[i]);

    int pos1=-1, posn=-1;
    foru(i,1,n){
        p[i]=p[i]-mi+1;
        if(p[i]==1) pos1=i;
        if(p[i]==n) posn=i;
    }

    if(pos1<posn){
        foru(i,1,n) answer(i,p[i]);
        return;
    }

    /// try with sign=1
    sign=1;
    p[1]=0; p[2]=sign*d2[1];
    foru(i,2,n-1){
        if(!isSame[i]) sign*=-1;
        p[i+1]=p[i]+sign*d2[i];
    }

    mi=0;
    foru(i,1,n) mini(mi,p[i]);

    pos1=-1, posn=-1;
    foru(i,1,n){
        p[i]=p[i]-mi+1;
        if(p[i]==1) pos1=i;
        if(p[i]==n) posn=i;
    }

    if(pos1<posn){
        foru(i,1,n) answer(i,p[i]);
        return;
    }
    assert(0); /// wtf is happening
}

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