Submission #653974

#	Time	Username	Problem	Language	Result	Execution time	Memory
653974		pavement	Cigle (COI21_cigle)	C++17	48 / 100	1099 ms	102344 KiB

cigle

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#ifdef _WIN32
#define getchar_unlocked _getchar_nolock
#endif
#define int long long
#define mp make_pair
#define mt make_tuple
#define pb push_back
#define ppb pop_back
#define eb emplace_back
#define g0(a) get<0>(a)
#define g1(a) get<1>(a)
#define g2(a) get<2>(a)
#define g3(a) get<3>(a)
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
using db = double;
using ll = long long;
using ld = long double;
using ii = pair<int, int>;
using iii = tuple<int, int, int>;
using iiii = tuple<int, int, int, int>;
template<class key, class value = null_type, class cmp = less<key> >
using ordered_set = tree<key, value, cmp, rb_tree_tag, tree_order_statistics_node_update>;

int N, ans, d[5005], p[5005], dp[5005][5005];

struct node {
	node *left, *right;
	int S, E, val, pv;
	node(int _s, int _e) : S(_s), E(_e), val(0), pv(0) {
		if (S == E) {
			return;
		}
		int M = (S + E) >> 1;
		left = new node(S, M);
		right = new node(M + 1, E);
	}
	void prop() {
		if (S == E || !pv) return;
		left->val += pv;
		left->pv += pv;
		right->val += pv;
		right->pv += pv;
		pv = 0;
	}
	void clear() {
		val = pv = 0;
		if (S != E) {
			left->clear();
			right->clear();
		}
	}
	void upd(int l, int r, int v) {
		if (l > E || r < S) return;
		if (l <= S && E <= r) {
			val += v;
			pv += v;
			return;
		}
		prop();
		left->upd(l, r, v);
		right->upd(l, r, v);
		val = max(left->val, right->val);
	}
} *root;

main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin >> N;
	for (int i = 1; i <= N; i++) {
		cin >> d[i];
		p[i] = p[i - 1] + d[i];
	}
	root = new node(1, N);
	for (int j = N; j >= 1; j--) {
		root->clear();
		for (int k = j + 1; k <= N; k++) {
			root->upd(k, k, dp[j + 1][k]);
		}
		for (int i = j; i >= 1; i--) {
			int lo = j + 1, hi = N, ans = -1;
			while (lo <= hi) {
				int mid = (lo + hi) >> 1;
				if (p[mid] - p[j] == p[j] - p[i - 1]) {
					ans = mid;
					break;
				} else if (p[mid] - p[j] > p[j] - p[i - 1]) hi = mid - 1;
				else lo = mid + 1;
			}
			dp[i][j] = root->val;
			//~ cout << "DP " << i << ' ' << j << ' ' << root->val << '\n';
			if (ans != -1) {
				root->upd(ans + 1, N, 1);
				//~ cout << " + " << i << ' ' << ans << '\n';
			}
		}
	}
	for (int i = 1; i <= N; i++) {
		ans = max(ans, dp[1][i]);
	}
	cout << ans << '\n';
}

Compilation message (stderr)

cigle.cpp:71:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   71 | main() {
      | ^~~~

• Subtask 1: 9 / 9
• Subtask 2: 11 / 11
• Subtask 3: 13 / 13
• Subtask 4: 15 / 15
• Subtask 5: 0 / 52