Submission #1294846

#	Time	Username	Problem	Language	Result	Execution time	Memory
1294846		azamurai	Bigger segments (IZhO19_segments)	C++20	13 / 100	7 ms	4424 KiB

segments

#include <bits/stdc++.h>

#define int long long
#define ll long long
#define mp make_pair
#define fi first 
#define se second 
#define Sz(x) (int)x.size()

using namespace std;

const int N = 3005;
const int inf = INT_MAX;
int n, a[N], dp[N][N], pref[N];

void solve() {
	cin >> n;
	for (int i = 1; i <= n; i++) {
		cin >> a[i];
		pref[i] = pref[i - 1] + a[i];
	}	
	for (int i = 0; i <= n; i++) {
		for (int j = 0; j <= n; j++) {
			dp[i][j] = inf;
		}
	}
	for (int i = 1; i <= n; i++) {
		dp[i][0] = 1;
	}
	for (int i = 2; i <= n; i++) {
		for (int j = 1; j < i; j++) {
			int posR = i;
			int posL = j + 1;
			int sum = pref[posR] - pref[posL - 1];
			int l = 0, r = j - 1, best = -1;
			while (l <= r) {
				int mid = (l + r) / 2;
				if ((pref[j] - pref[mid]) > sum) l = mid + 1;
				else {
					r = mid - 1;
					best = mid;
				}
			}
			if (best == -1) continue;
			l = best, r = j - 1, best = -1;
			while (l <= r) {
				int mid = (l + r) / 2;
				if (dp[j][mid] == inf) r = mid - 1;
				else {
					l = mid + 1;
					best = mid;
				}
			}
			if (best != -1) dp[i][j] = dp[j][best] + 1;
		}
	}
	int ans = 0;
	for (int i = 0; i < n; i++) {
		if (dp[n][i] != inf) ans = max(ans, dp[n][i]);
	}
	cout << ans;
}

signed main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);

	int tt = 1;
	// cin >> tt;
	while (tt--) {
		solve();
		cout << '\n';
	}
}

• Subtask 1: 13 / 13
• Subtask 2: 0 / 14
• Subtask 3: 0 / 10
• Subtask 4: 0 / 36
• Subtask 5: 0 / 27