Submission #1159968

#TimeUsernameProblemLanguageResultExecution timeMemory
1159968jmyszka2007Cigle (COI21_cigle)C++17
100 / 100
625 ms98664 KiB
#include <bits/stdc++.h>
#include <fstream>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/trie_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
template<class A, class B>
ostream& operator<<(ostream& o, const pair<A, B>& p) {return o << '(' << p.first << ", " << p.second << ')';}
template<size_t Index = 0, typename... Types>
ostream& printTupleElements(ostream& o, const tuple<Types...>& t) {if constexpr (Index < sizeof...(Types)){if(Index > 0){o << ", ";}o << get<Index>(t);printTupleElements<Index + 1>(o, t);}return o;}
template<typename... Types>
ostream& operator<<(ostream& o, const tuple<Types...>& t){o << "(";printTupleElements(o, t);return o << ")";}
template<class T>
auto operator<<(ostream& o, const T& x) -> decltype(x.end(), o){o << '{';bool first = true;for (const auto& e : x){if (!first){o << ", ";}o << e;first = false;} return o << '}';}
struct custom_hash {static uint64_t splitmix64(uint64_t x) {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);}};
//#define DEBUG
#ifdef DEBUG
#define fastio()
#define debug(x...) cerr << "[" #x "]: ", [](auto... $) {((cerr << $ << "; "), ...); }(x), cerr << '\n'
#else
#define fastio() ios_base::sync_with_stdio(0); cin.tie(0);
#define debug(...)
#endif
typedef long long ll;
#define pi pair<int, int>
#define pll pair<ll, ll>
#define st first
#define nd second
#define vi vector<int>
#define vll vector<ll>
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
typedef tree<int, null_type, less<int>, rb_tree_tag,tree_order_statistics_node_update> ordered_set;
void solve() {
	//ifstream cin("nazwa.in");
	//ofstream cout("nazwa.out");
	int n;
	cin >> n;
	vi T(n + 1);
	for(int i = 1; i <= n; i++) {
		cin >> T[i];
	}
	vector<vi>dp(n + 1, vi(n + 1, 0));
	int ans = 0;
	for(int i = 2; i <= n; i++) {
		int base = 1;
		while(base <= n) {
			base *= 2;
		}
		vi tri(2 * base, 0), lazy(2 * base, 0);
		for(int j = 1; j < i; j++) {
			tri[j + base - 1] = dp[j][i - 1];
		}
		for(int j = base - 1; j >= 1; j--) {
			tri[j] = max(tri[2 * j], tri[2 * j + 1]);
		}
		auto spl = [&](int v) {
			tri[2 * v] += lazy[v];
			lazy[2 * v] += lazy[v];
			tri[2 * v + 1] += lazy[v];
			lazy[2 * v + 1] += lazy[v];
			lazy[v] = 0;
		};
		auto upd = [&](auto &&upd, int v, int l, int r, int a, int b, int x) -> void {
			if(r < a || l > b) {
				return;
			}
			if(a <= l && r <= b) {
				tri[v] += x;
				lazy[v] += x;
				return;
			}
			spl(v);
			int mid = (l + r) / 2;
			upd(upd, 2 * v, l, mid, a, b, x);
			upd(upd, 2 * v + 1, mid + 1, r, a, b, x);
			tri[v] = max(tri[2 * v], tri[2 * v + 1]);
		};
		int k = i - 1, sum_D = T[k], sum_G = 0;
		for(int j = i; j <= n; j++) {
			sum_G += T[j];
			while(k > 1 && sum_D < sum_G) {
				k--;
				sum_D += T[k];
			}
			dp[i][j] = tri[1];
			if(sum_D == sum_G) {
				upd(upd, 1, 1, base, 1, k - 1, 1);
			}
			ans = max(ans, dp[i][j]);
		}
	}
	cout << ans << '\n';
}
int main() {
	fastio();
	int t = 1;
	//cin >> t;
	while(t--) {
		solve();
	}
}
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