Submission #996227

#	Time	Username	Problem	Language	Result	Execution time	Memory
996227		reginox	Xylophone (JOI18_xylophone)	C++17	100 / 100	171 ms	952 KiB

xylophone

#include<bits/stdc++.h>
#include "xylophone.h"
#define ll long long
#define all(v) begin(v), end(v)
#define pi pair<int, int>
#define vi vector<int>
using namespace std;
int a[5005], n;
int p1[5005], p2[5005];
 
bool thu(int u, int v){
    if(v < 1 || v > n) return false;
    a[1] = u, a[2] = v;
    for(int i = 3; i <= n; i++){
        int d1 = p1[i], d2 = p2[i], d3 = abs(a[i-2] - a[i-1]);
        if(a[i-2] > a[i-1]){
            if(d1 == d2 || d2 == d3){
                a[i] = a[i-1] + d1;
            }
            else{
               a[i] = a[i-1] - d1; 
            }
        }
        else{
            if(d1 == d2 || d2 == d3){
                a[i] = a[i-1] - d1;
            }
            else{
               a[i] = a[i-1] + d1; 
            }
        }
    }
    vector<bool> ch(n, false);
    for(int i = 1; i <= n; i++){
        if(a[i] < 1 || a[i] > n) return false;
        if(ch[a[i]-1]) return false;
        if(a[i] == n && !ch[0]) return false;
        ch[a[i]-1] = true;
    }
    return true;
}
 
void solve(int m){
    n = m;
    int d = query(1, 2);
    for(int i = 3; i <= n; i++){
        p1[i] = query(i-1, i), p2[i] = query(i-2, i);
    }
    for(int v1 = 1; v1 <= n; v1++){
        for(int z = -d; z <= d; z+=2*d){
            if(thu(v1, v1+z)){
                for(int i = 1; i <= n; i++) answer(i, a[i]);
                return ;
            }
        }
    }
}

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