Submission #1356062

#TimeUsernameProblemLanguageResultExecution timeMemory
1356062crispxxXylophone (JOI18_xylophone)C++20
100 / 100
15 ms1112 KiB
#include "xylophone.h"

#include <bits/stdc++.h>

using namespace std;

#define nl '\n'

using ll = long long;

map<array<int, 2>, int> mp;

int ask(int l, int r) {
	if(mp.count({l, r})) return mp[{l, r}];
	return mp[{l, r}] = query(l + 1, r + 1);
}

int find_one(int n) {
	int l = 0, r = n - 1;
	
	while(l < r) {
		int mid = (l + r + 1) >> 1;
		
		if(ask(mid, n - 1) == n - 1) l = mid;
		else r = mid - 1;
	}
	
	return l;
}

void solve(int n) {
	int i1 = find_one(n);
	
	vector<int> a(n);
	
	a[i1] = 1;
	
	set<int> used;
	
	used.emplace(1);
	
	auto can = [&](int x) {
		return x >= 1 && x <= n && !used.count(x);
	};
	
	vector<int> dif(n);
	
	for(int i = 1; i < n; i++) {
		dif[i] = ask(i - 1, i);
	}
	
	for(int i = i1 + 1; i < n; i++) {
		bool bigger = false;
		
		int x = dif[i];
		
		if(i == i1 + 1) {
			bigger = true;
		} else if(!can(a[i - 1] + x)) {
			// less
		} else if(!can(a[i - 1] - x)) {
			bigger = true;
		} else {
			int y = ask(i - 2, i);
			
			if(a[i - 2] < a[i - 1]) {
				if(dif[i - 1] + dif[i] == y) {
					bigger = true;
				} else {
					// less
				}
			} else {
				if(dif[i - 1] + dif[i] == y) {
					// less
				} else {
					bigger = true;
				}
			}
			
		}
		
		a[i] = a[i - 1] + (bigger ? x : -x);
		
		used.emplace(a[i]);
	}
	
	for(int i = i1 - 1; i >= 0; i--) {
		bool bigger = false;
		
		int x = dif[i + 1];
		
		if(i == i1 - 1) {
			bigger = true;
		} else if(!can(a[i + 1] + x)) {
			// less
		} else if(!can(a[i + 1] - x)) {
			bigger = true;
		} else {
			int y = ask(i, i + 2);
			
			if(a[i + 2] < a[i + 1]) {
				if(dif[i + 2] + dif[i + 1] == y) {
					bigger = true;
				} else {
					// less
				}
			} else {
				if(dif[i + 2] + dif[i + 1] == y) {
					// less
				} else {
					bigger = true;
				}
			}
			
		}
		
		a[i] = a[i + 1] + (bigger ? x : -x);
		
		used.emplace(a[i]);
	}
	
	// cout << "here: " << nl;
	
	// for(int i = 0; i < n; i++) {
		// cout << a[i] << ' ';
	// }
	
	// cout << nl;
	
	for(int i = 0; i < n; i++) answer(i + 1, a[i]);
}

/**

**/

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