Submission #545291

#	Time	Username	Problem	Language	Result	Execution time	Memory
545291		Jomnoi	Xylophone (JOI18_xylophone)	C++17	47 / 100	84 ms	416 KiB

xylophone

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

static int A[5000];

namespace {

const int MAX_N = 5e3 + 10;

int result, lowest, highest;
int ans[MAX_N];

int findFromRight(int l, int r, int diff) {
	int res = -1;
	int leftmost = l;
	while(l <= r) {
		int mid = (l + r) / 2;

		if(query(leftmost, mid) == diff) {
			res = mid;
			r = mid - 1;
		}
		else {
			l = mid + 1;
		}
	}
	return res;
}

int findFromLeft(int l, int r, int diff) {
	int res = -1;
	int rightmost = r;
	while(l <= r) {
		int mid = (l + r) / 2;

		if(query(mid, rightmost) == diff) {
			res = mid;
			l = mid + 1;
		}
		else {
			r = mid - 1;
		}
	}
	return res;
}

void solveLeft(int l, int r, bool state) {
	if(l >= r) {
		return;
	}

	int diff = query(l, r);
	int res = findFromLeft(l, r, diff);

	if(state == false) {
		ans[res] = ans[r] + diff;
	}
	else {
		ans[res] = ans[r] - diff;
	}

	solveLeft(l, res, state ^ true);
	solveLeft(res + 1, r, state);
}

void solveRight(int l, int r, bool state) {
	if(l >= r) {
		return;
	}

	int diff = query(l, r);
	int res = findFromRight(l, r, diff);

	if(state == false) {
		ans[res] = ans[l] + diff;
	}
	else {
		ans[res] = ans[l] - diff;
	}

	solveRight(l, res - 1, state);
	solveRight(res, r, state ^ true);
}

void solveMiddle(int l, int r, bool state) {
	if(l >= r) {
		return;
	}

	int diff = query(l, r);
	int res = findFromRight(l, r, diff);

	if(state == false) {
		ans[res] = ans[l] + diff;
	}
	else {
		ans[res] = ans[l] - diff;
	}

	solveMiddle(l, res - 1, state);
	solveMiddle(res, r, state ^ true);
}

}

void solve(int N) {
	// Find the highest pitch
	result = findFromRight(1, N, N - 1);
	ans[result] = N;
	highest = result;

	// Find the lowest pitch
	result = findFromLeft(1, highest, N - 1);
	ans[result] = 1;
	lowest = result;

	// Solve
	solveLeft(1, lowest, false);
	solveRight(highest, N, true);
	solveMiddle(lowest, highest - 1, false);

	// Answer
	for(int i = 1; i <= N; i++) {
		answer(i, ans[i]);
	}
}

Compilation message (stderr)

xylophone.cpp:5:12: warning: 'A' defined but not used [-Wunused-variable]
    5 | static int A[5000];
      |            ^

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