Submission #1198431

#	Time	Username	Problem	Language	Result	Execution time	Memory
1198431		aykhn	Bigger segments (IZhO19_segments)	C++20	37 / 100	168 ms	72828 KiB

segments

#include <bits/stdc++.h>

using namespace std;

#define int long long
#define inf 0x3F3F3F3F3F3F3F3F

const int MXN = 3e3 + 5;
const int mod = 1e9 + 7;

int dp[MXN][MXN];

void _()
{
  int n;
  cin >> n;
  int a[n + 1], p[n + 1];
  for (int i = 1; i <= n; i++) cin >> a[i];
  p[0] = 0;
  for (int i = 1; i <= n; i++) p[i] = p[i - 1] + a[i];
  auto sum = [&](int l, int r)
  {
    if (l > r) return 0LL;
    return p[r] - (l ? p[l - 1] : 0LL);
  };
  auto findmid = [&](int l, int r)
  {
    int lx = l, rx = r;
    while (lx < rx)
    {
      int mid = (lx + rx + 1) >> 1;
      if (sum(l, mid - 1) <= sum(mid, r)) lx = mid;
      else rx = mid - 1;
    }
    return lx;
  };
  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[1][i] = 1;
    for (int j = 1; j <= i; j++)
    {
      int k = findmid(j, i);
      if (k > j) dp[k][i] = max(dp[k][i], dp[j][k - 1] + 1);
    }
  }
  int res = 1;
  for (int i = 1; i <= n; i++) res = max(res, dp[i][n]);
  cout << res << '\n';
}

signed main()
{
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int t = 1;
  // cin >> t;
  while (t--) _();
}

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