Submission #553513

#	Time	Username	Problem	Language	Result	Execution time	Memory
553513		Tien_Noob	Split the sequence (APIO14_sequence)	C++17	100 / 100	1354 ms	83756 KiB

sequence

//Make CSP great again
//Vengeance
#include <bits/stdc++.h>
#define TASK "TESTCODE"
#define Log2(x) 31 - __builtin_clz(x)
using namespace std;
const int N = 1e5, K = 2e2;
long long f[N + 1], dp[N + 1][2];
int p[N + 1][K + 1];
int n, k;
struct Convex
{
    deque<long double> inter;
    deque<long long> A, B;
    deque<int> pos;
    void reset()
    {
        pos = {0};
        inter = {-1e18};
        A = {0};
        B = {0};
    }
    long double Intersect(int i, int j)
    {
        return (long double)(B[j] - B[i])/(A[i] - A[j]);
    }
    bool ok(long long a, long long b)
    {
        long double x1 = (long double)(B[A.size() - 2] - b)/(a - A[A.size() - 2]);
        return x1 > Intersect(A.size() - 2, A.size() - 1);
    }
    void add(int i, long long a, long long b)
    {
        if (A.back() == a)
        {
            if (b >= B.back())
            {
                pos.pop_back();
                A.pop_back();
                B.pop_back();
                inter.pop_back();
                if (inter.empty())
                {
                    pos = {i};
                    inter = {-1e18};
                    A = {a};
                    B = {b};
                }
                else
                {
                    pos.push_back(i);
                    A.push_back(a);
                    B.push_back(b);
                    inter.push_back(Intersect(A.size() - 2, A.size() - 1));
                }
            }
            return ;
        }
        while(inter.size() >= 2 && !ok(a, b))
        {
            inter.pop_back();
            A.pop_back();
            B.pop_back();
            pos.pop_back();
        }
        pos.push_back(i);
        A.push_back(a);
        B.push_back(b);
        inter.push_back(Intersect(A.size() - 2, A.size() - 1));
    }
    long long get(long long x)
    {
        while(inter.size() >= 2 && inter[1] <= x)
        {
            inter.pop_front();
            A.pop_front();
            B.pop_front();
            pos.pop_front();
        }
        return A.front() * x + B.front();
    }
} CHT;
void read()
{
    cin >> n >> k;
    for (int i = 1; i <= n; ++ i)
    {
        cin >> f[i];
        f[i] = f[i - 1] + f[i];
    }
}
void Traceback(int i, int j)
{
    if (j == 0)
    {
        return ;
    }
    cout << p[i][j] << ' ';
    Traceback(p[i][j], j - 1);
}
void solve()
{
    for (int j = 1; j <= k; ++ j)
    {
        CHT.reset();
        for (int i = 1; i <= n; ++ i)
        {
            int cur = j & 1;
            dp[i][cur] = CHT.get(f[i]);
            p[i][j] = CHT.pos.front();
            CHT.add(i, f[i], dp[i][cur ^ 1] - f[i] * f[i]);
        }
    }
    cout << dp[n][k & 1] << '\n';
    Traceback(n, k);
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    if (fopen(TASK".INP", "r"))
    {
        freopen(TASK".INP", "r", stdin);
        //freopen(TASK".OUT", "w", stdout);
    }
    int t = 1;
    bool typetest = false;
    if (typetest)
    {
        cin >> t;
    }
    for (int __ = 1; __ <= t; ++ __)
    {
        //cout << "Case " << __ << ": ";
        read();
        solve();
    }
}

Compilation message (stderr)

sequence.cpp: In function 'int main()':
sequence.cpp:123:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  123 |         freopen(TASK".INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 11 / 11
• Subtask 3: 11 / 11
• Subtask 4: 17 / 17
• Subtask 5: 21 / 21
• Subtask 6: 29 / 29