Submission #1189831

#	Time	Username	Problem	Language	Result	Execution time	Memory
1189831		countless	Packing Biscuits (IOI20_biscuits)	C++20	100 / 100	10 ms	952 KiB

biscuits

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

typedef long long ll;
typedef long double ld;

const ll MOD = 998244353;
const ll INF = 1e18;
const ld EPS = 1e-12;

#define endl "\n"
#define sp <<" "<<
#define REP(i, a, b) for(ll i = a; i < b; i++)
#define dbg(x) cout << #x << " = " << x << endl
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define fast_io() ios_base::sync_with_stdio(false); cin.tie(NULL)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(x) ((ll)(x).size())

struct custom_hash {
	static uint64_t splitmix64(uint64_t x) {
		// http://xorshift.di.unimi.it/splitmix64.c
		x += 0x9e3779b97f4a7c15;
		x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
		x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
		return x ^ (x >> 31);
	}

	size_t operator()(uint64_t x) const {
		static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
		return splitmix64(x + FIXED_RANDOM);
	}
};

template <typename Key, typename Value>
using hash_map = unordered_map<Key, Value, custom_hash>;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
// uniform_int_distribution<int>(a, b)(rng);
// shuffle(all(a), rng);

// recall the editorial solution
// why does this hold true?
// O(k^2)
ll count_tastiness(ll x, vector<ll> a) {
	a.resize(61, 0LL);
	vector<ll> dp(61);
	vector<ll> threshold(61);
	
	dp[0] = 1;

	ll sum = 0;
	REP(i, 1, 61) {
		sum += (a[i-1] << (i-1));
		ll mx = sum / x;
		threshold[i] = mx;

		for (int j = i - 1; j >= 0; j--) {
			if (j == 0) { // special case
				if (mx >= 1) {
					dp[i] += 2;
				} else {
					dp[i]++;
				}
			} else if (mx >= (2LL << j)) { // over threshold
				dp[i] += 2LL * dp[j];
				break;
			} else if (mx >= (1LL << j)) { // what
				dp[i] += dp[j];
				mx = min(mx - (1LL << j), threshold[j]);
			} else { // what
				mx = min(mx, threshold[j]);
			}
		}
	}

	return dp[60];
}

// signed main() {
// 	ll t; cin >> t;
// 	while (t--) {
// 		ll k, x; cin >> k >> x;
// 		vector<ll> a(k);
// 		REP(i, 0, k)
// 			cin >> a[i];

// 		cout << count_tastiness(x, a) << endl;
// 	}
// }

• Subtask 1: 9 / 9
• Subtask 2: 12 / 12
• Subtask 3: 21 / 21
• Subtask 4: 35 / 35
• Subtask 5: 23 / 23