Submission #1168954

#	Time	Username	Problem	Language	Result	Execution time	Memory
1168954		MateiKing80	Distributing Candies (IOI21_candies)	C++20	100 / 100	659 ms	25616 KiB

candies

#include "candies.h"
#include <bits/stdc++.h>

using namespace std;

struct Buckets 
{
	int n;
	int bucket_size, bucket_cnt;
	vector<int> vals;
	vector<long long> mini, maxi, sums;
	Buckets(int _n): n(_n) 
	{
		bucket_size = sqrt(n);
		bucket_cnt = (n + bucket_size - 1) / bucket_size;
		vals.assign(n, 0);
		mini.assign(bucket_cnt, 0);
		maxi.assign(bucket_cnt, 0);
		sums.assign(bucket_cnt, 0);
	}

	void update(int x, int val) 
	{
		vals[x] = val;
		int bucket = x / bucket_size;

		mini[bucket] = maxi[bucket] = sums[bucket] = 0;
		for (int i = min(n, (bucket + 1) * bucket_size) - 1; i >= bucket * bucket_size; i --) 
		{
			sums[bucket] += vals[i];
			maxi[bucket] = max(maxi[bucket], sums[bucket]);
			mini[bucket] = min(mini[bucket], sums[bucket]);		
		}
	}

	tuple<int, int, int> query(int c) 
	{
		int sufsum = 0, sufmin = 0, sufmax = 0;
		for (int bucket = bucket_cnt - 1; bucket >= 0; --bucket) 
		{
			long long nsufsum = sufsum + sums[bucket],
					  nsufmin = min(1LL * sufmin, sufsum + mini[bucket]),
					  nsufmax = max(1LL * sufmax, sufsum + maxi[bucket]);
			if (nsufmax - nsufmin > c) 
			{
				for (int i = min(n, (bucket + 1) * bucket_size) - 1; i >= bucket * bucket_size; i --) 
				{
					sufsum += vals[i];
					sufmin = min(sufmin, sufsum);
					sufmax = max(sufmax, sufsum);
					if (sufmax - sufmin > c) 
						return make_tuple(sufmin, sufmax, i);
				}
		  }
		  sufsum = nsufsum; sufmax = nsufmax; sufmin = nsufmin;
		}
		return make_tuple(sufmin, sufmax, 0);
  }

  inline int at(int x) { return vals[x]; }
};

vector<int> distribute_candies(vector<int> c, vector<int> l, vector<int> r, vector<int> v) 
{
	int n = c.size(), q = v.size();
	vector<vector<pair<int, int>>> queriesL(n), queriesR(n);
	for (int i = 0; i < q; i ++)
	{
		queriesL[l[i]].emplace_back(i, v[i]);
		queriesR[r[i]].emplace_back(i, v[i]);
	}

	vector<int> s(n);
	Buckets tree(q);
	for (int i = 0; i < n; i ++)
	{ 
		for (auto [idx, val] : queriesL[i])
			tree.update(idx, -val);

		auto [mini, maxi, idx] = tree.query(c[i]);
		if (maxi - mini <= c[i])
			s[i] = -mini;
		else if (tree.at(idx) < 0)
			s[i] = c[i] - maxi;
		else
			s[i] = -mini;

		for (auto [idx, val] : queriesR[i])
		  tree.update(idx, 0);
	}

	return s;
}

• Subtask 1: 3 / 3
• Subtask 2: 8 / 8
• Subtask 3: 27 / 27
• Subtask 4: 29 / 29
• Subtask 5: 33 / 33