Submission #702811

#	Time	Username	Problem	Language	Result	Execution time	Memory
702811		yhkhoo	Xylophone (JOI18_xylophone)	C++17	0 / 100	97 ms	208 KiB

xylophone

#include "xylophone.h"
#include <bits/stdc++.h>
using namespace std;
static int A[5001];

void solve(int N) {
	//bs for 1
	int s=1, e=N-1;
	while(s!=e){
		int mid = (s+e)/2;
		if(query(mid, N) != N-1){
			e = mid-1;
		}
		else{
			s = mid;
		}
	}
	A[s] = 1;
	unordered_set<int> aset;
	aset.insert(1);
	if(s-1 != 0){
		A[s-1] = query(s-1, s)+1;
		aset.insert(A[s-1]);
	}
	for(int i=s-2; i>0; i--){ // go to the left
		int temp1 = query(i, i+1);
		if(A[i+1] - temp1 < 2 || aset.count(A[i+1] - temp1)){ // not possible to be less 
			A[i] = A[i+1] + temp1;
		}
		else if(A[i+1] + temp1 > N || aset.count(A[i+1] + temp1)){ // not possible to be more
			A[i] = A[i+1] - temp1;
		}
		else{ // can be both
			int temp2 = query(i, i+2);
			if(temp1 == temp2){ // A[i+2] is inbetween A[i+1] and A[i]
				if(A[i+2] > A[i+1]){
					A[i] = A[i+1] + temp1;
				}
				else{
					A[i] = A[i+1] - temp1;
				}
			}
			else{ // A[i+2] is outside of the range of A[i+1] and A[i]
				if(A[i+2] > A[i+1]){
					if(temp2 == A[i+2] - A[i+1]){ // A[i] is inbetween A[i+2] and A[i+1]
						A[i] = A[i+1] + temp1;
					}
					else{
						A[i] = A[i+1] - temp1;
					}
				}
				else{
					if(temp2 == A[i+1] - A[i+2]){ // A[i] is inbetween A[i+2] and A[i+1]
						A[i] = A[i+1] - temp1;
					}
					else{
						A[i] = A[i+1] + temp1;
					}
				}
			}
		}
		aset.insert(A[i]);
	}
	A[s+1] = query(s, s+1)+1;
	aset.insert(A[s+1]);
	for(int i=s+2; i<=N; i++){ // go to the right
		int temp1 = query(i-1, i);
		 	if(A[i-1] - temp1 < 2 || aset.count(A[i-1] - temp1)){ // not possible to be less 
			A[i] = A[i-1] + temp1;
		}
		else if(A[i-1] + temp1 > N || aset.count(A[i-1] + temp1)){ // not possible to be more
			A[i] = A[i-1] - temp1;
		}
		else{ // can be both
			int temp2 = query(i-2, i);
			if(temp1 == temp2){ // A[i-2] is inbetween A[i-1] and A[i]
				if(A[i-2] > A[i-1]){
					A[i] = A[i-1] + temp1;
				}
				else{
					A[i] = A[i-1] - temp1;
				}
			}
			else{ // A[i-2] is outside of the range of A[i-1] and A[i]
				if(A[i-2] > A[i-1]){
					if(temp2 == A[i-2] - A[i-1]){ // A[i] is inbetween A[i-2] and A[i-1]
						A[i] = A[i-1] + temp1;
					}
					else{
						A[i] = A[i-1] - temp1;
					}
				}
				else{
					if(temp2 == A[i-1] - A[i-2]){ // A[i] is inbetween A[i-2] and A[i-1]
						A[i] = A[i-1] - temp1;
					}
					else{
						A[i] = A[i-1] + temp1;
					}
				}
			}
		}
		aset.insert(A[i]);
	}
	
	for(int i = 1; i <= N; i++) {
		answer(i, A[i]);
	}
	
}

• Subtask 1: 0 / 11
• Subtask 2: 0 / 36
• Subtask 3: 0 / 53