Submission #407439

#	Time	Username	Problem	Language	Result	Execution time	Memory
407439		534351	Cigle (COI21_cigle)	C++17	100 / 100	368 ms	67472 KiB

cigle

#include <bits/stdc++.h>

using namespace std;

template<class T, class U>
void ckmin(T &a, U b)
{
    if (a > b) a = b;
}

template<class T, class U>
void ckmax(T &a, U b)
{
    if (a < b) a = b;
}

#define MP make_pair
#define PB push_back
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
#define FOR(i, a, b) for (auto i = (a); i < (b); i++)
#define FORD(i, a, b) for (auto i = (a) - 1; i >= (b); i--)
#define SZ(x) ((int) (x).size())
#define ALL(x) (x).begin(), (x).end()

const int MAXN = 5013;

typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<pii> vpi;
typedef vector<pll> vpl;

int N;
int arr[MAXN], pref[MAXN];
int dp[MAXN][MAXN];
int ans;
int fen[MAXN];

void update(int idx, int i)
{
    for (int e = idx + 1; e <= i; e += e & (-e))
    {
        fen[e]++;
    }
}
int query(int idx)
{
    int res = 0;
    for (int e = idx + 1; e; e -= e & (-e))
    {
        res += fen[e];
    }
    return res;
}

int32_t main()
{
    ios_base::sync_with_stdio(false); cin.tie(0);
    cout << fixed << setprecision(12);
    cerr << fixed << setprecision(4);
    cin >> N;
    FOR(i, 0, N)
    {
        cin >> arr[i];
        pref[i + 1] = pref[i] + arr[i];
    }
    // dp[0][0] = 0;
    FOR(i, 2, N + 1)
    {
        fill(fen, fen + N + 2, 0);
        set<int> cands;
        int best = 0;
        FOR(j, 1, i)
        {
            ckmax(dp[j][i - 1], dp[j - 1][i - 1]);
        }
        best = dp[i - 1][i - 1];
        int iter = i - 1;
        FOR(j, i, N + 1)
        {
            dp[i][j] = best;
            int c = 2 * pref[i - 1] - pref[j];
            while(iter != 0 && pref[iter] > c)
            {
                iter--;
            }
            if (pref[iter] == c)
            {
                update(i - iter, i);
                ckmax(best, dp[iter][i - 1] + query(i - iter));
            }
        }
    }
    FOR(i, 1, N + 1)
    {
        ckmax(ans, dp[i][N]);
    }
    cout << ans << '\n';
    return 0;
}

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