Submission #1049206

#	Time	Username	Problem	Language	Result	Execution time	Memory
1049206		DeathIsAwe	Xylophone (JOI18_xylophone)	C++17	0 / 100	0 ms	344 KiB

xylophone

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

int a[5001];
bool solved[5001];

void solve(int n) {
	for (int i=0;i<5001;i++) {
		a[i] = -1;
		solved[i] = false;
	}


	int bottom = 1, top = n, middle, diff, diff2;
	while (bottom + 1 < top) {
		middle = (top + bottom) / 2;
		diff = query(1, middle);
		if (diff == n - 1) {
			top = middle;
		} else {
			bottom = middle;
		}
	}



	a[top] = n; solved[n] = true; answer(top, n);
	if (top != n) {
		a[top + 1] = n - query(top, top + 1);
		solved[a[top + 1]] = true; answer(top + 1, a[top + 1]);
	}
	a[top - 1] = n - query(top - 1, top);
	solved[a[top - 1]] = true; answer(top - 1, a[top - 1]);
	for (int i=top+2;i<n+1;i++) {
		diff = query(i - 1, i);
		if (a[i - 1] - diff < 1 || solved[a[i - 1] - diff]) {
			a[i] = a[i - 1] + diff;
		} else  if (a[i - 1] + diff > n || solved[a[i - 1] + diff]) {
			a[i] = a[i - 1] - diff;
		} else {
			diff2 = query(i - 2, i);
			if (a[i - 2] > a[i - 1]) {
				if (diff2 == a[i - 2] - a[i - 1] + diff) {
					a[i] = a[i - 1] - diff;
				} else {
					a[i] = a[i - 1] + diff;
				}
			} else {
				if (diff2 == a[i - 1] - a[i - 2] + diff) {
					a[i] = a[i - 1] + diff;
				} else {
					a[i] = a[i - 1] - diff;
				}
			}
		}
		solved[a[i]] = true; answer(i, a[i]);
	}
	for (int i=top-2;i>0;i--) {
		diff = query(i, i + 1);
		if (a[i + 1] - diff < 1 || solved[a[i - 1] - diff]) {
			a[i] = a[i + 1] + diff;
		} else if (a[i + 1] + diff > n || solved[a[i + 1] + diff]) {
			a[i] = a[i + 1] - diff;
		} else {
			diff2 = query(i, i + 2);
			if (a[i + 2] > a[i + 1]) {
				if (diff2 == a[i + 2] - a[i + 1] + diff) {
					a[i] = a[i + 1] - diff;
				} else {
					a[i] = a[i + 1] + diff;
				}
			} else {
				if (diff2 == a[i + 1] - a[i + 2] + diff) {
					a[i] = a[i + 1] + diff;
				} else {
					a[i] = a[i + 1] - diff;
				}
			}
		}
		solved[a[i]] = true; answer(i, a[i]);
	}
}

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