Submission #653981

#	Time	Username	Problem	Language	Result	Execution time	Memory
653981		pavement	Cigle (COI21_cigle)	C++17	48 / 100	1089 ms	60196 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, t[10005], d[5005], p[5005], dp[5005][5005];

const int h = sizeof(int) * 8 - __builtin_clz(5000);

void apply(int p, int value) {
  t[p] += value;
  if (p < N) d[p] += value;
}

void build(int p) {
  while (p > 1) p >>= 1, t[p] = max(t[p<<1], t[p<<1|1]) + d[p];
}

void push(int p) {
  for (int s = h; s > 0; --s) {
    int i = p >> s;
    if (d[i] != 0) {
      apply(i<<1, d[i]);
      apply(i<<1|1, d[i]);
      d[i] = 0;
    }
  }
}

void inc(int l, int r, int value) {
  l += N, r += N;
  int l0 = l, r0 = r;
  for (; l < r; l >>= 1, r >>= 1) {
    if (l&1) apply(l++, value);
    if (r&1) apply(--r, value);
  }
  build(l0);
  build(r0 - 1);
}

int query(int l, int r) {
  l += N, r += N;
  push(l);
  push(r - 1);
  int res = -2e9;
  for (; l < r; l >>= 1, r >>= 1) {
    if (l&1) res = max(res, t[l++]);
    if (r&1) res = max(t[--r], res);
  }
  return res;
}

main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin >> N;
	for (int i = 1; i <= N; i++) {
		cin >> p[i];
		p[i] += p[i - 1];
	}
	for (int j = N; j >= 1; j--) {
		memset(t, 0, sizeof t);
		memset(d, 0, sizeof d);
		for (int k = j + 1; k <= N; k++) {
			inc(k - 1, k, dp[j + 1][k]);
		}
		int ptr = j + 1;
		for (int i = j; i >= 1; i--) {
			int ans = -1;
			while (ptr <= N && p[ptr] - p[j] < p[j] - p[i - 1]) ptr++;
			if (ptr <= N && p[ptr] - p[j] == p[j] - p[i - 1]) ans = ptr;
			dp[i][j] = query(0, N);
			assert(dp[i][j] >= dp[i + 1][j]);
			//~ cout << "DP " << i << ' ' << j << ' ' << root->val << '\n';
			if (ans != -1) {
				inc(ans, 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:76:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   76 | main() {
      | ^~~~

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