Submission #1048734

#	Time	Username	Problem	Language	Result	Execution time	Memory
1048734		manhlinh1501	Split the sequence (APIO14_sequence)	C++17	50 / 100	2097 ms	32680 KiB

sequence

#include <bits/stdc++.h>
using namespace std;
using pii = pair<int, int>;
using i64 = long long;
const int MAXN = 1e4 + 5;
const int MAXK = 205;
#define ALL(a) (a).begin(), (a).end()
int N, K;
int a[MAXN];
i64 prefix[MAXN];

struct Line {
    mutable long long k, m, p;
    bool operator<(const Line& o) const {
        return k < o.k;
    }
    bool operator<(long long x) const {
        return p < x;
    }
};

struct LineContainer : multiset<Line, less<>> {
    // (for doubles, use inf = 1/.0, div(a,b) = a/b)
    static const long long inf = LLONG_MAX;
    long long div(long long a, long long b) { // floored division
        return a / b - ((a ^ b) < 0 && a % b);
    }
    bool isect(iterator x, iterator y) {
        if (y == end()) return x->p = inf, 0;

        if (x->k == y->k) x->p = x->m > y->m ? inf : -inf;
        else x->p = div(y->m - x->m, x->k - y->k);

        return x->p >= y->p;
    }
    void add(long long k, long long m) {
        auto z = insert({k, m, 0}), y = z++, x = y;

        while (isect(y, z)) z = erase(z);

        if (x != begin() && isect(--x, y)) isect(x, y = erase(y));

        while ((y = x) != begin() && (--x)->p >= y->p)
            isect(x, erase(y));
    }
    long long query(long long x) {
        assert(!empty());
        auto l = *lower_bound(x);
        return l.k * x + l.m;
    }
};


namespace subtask {
    i64 dp[MAXN][MAXK];
    pii trace[MAXN][MAXK];

    void solution() {
        K++;
        memset(dp, -0x3f, sizeof dp);
        dp[0][0] = 0;
        for(int z = 1; z <= K; z++) {
            for(int i = 1; i <= N; i++) {
                for(int j = 1; j <= i; j++) {
                    if(dp[i][z] < dp[j - 1][z - 1] + prefix[i] * prefix[N] - prefix[i] * prefix[i] - prefix[j - 1] * prefix[N] + prefix[j - 1] * prefix[i]) {
                        dp[i][z] = dp[j - 1][z - 1] + prefix[i] * prefix[N] - prefix[i] * prefix[i] - prefix[j - 1] * prefix[N] + prefix[j - 1] * prefix[i];
                        trace[i][z] = {j - 1, z - 1};
                    }
                }
            }
        }
        pii cur = {N, K};
        printf("%lld\n", dp[N][K]);
        for(int i = 1; i < K; i++) {
            cur = trace[cur.first][cur.second];
            printf("%d ", cur.first);
        }
    }
}

signed main() {
#define TASK "code"

    if (fopen(TASK ".inp", "r")) {
        freopen(TASK ".inp", "r", stdin);
        freopen(TASK ".out", "w", stdout);
    }

    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    cin >> N >> K;
    for(int i = 1; i <= N; i++) cin >> a[i];
    for(int i = 1; i <= N; i++) prefix[i] = prefix[i - 1] + a[i];
    subtask::solution();
    return (0 ^ 0);
}

Compilation message (stderr)

sequence.cpp: In function 'int main()':
sequence.cpp:85:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   85 |         freopen(TASK ".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
sequence.cpp:86:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   86 |         freopen(TASK ".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 11 / 11
• Subtask 3: 11 / 11
• Subtask 4: 17 / 17
• Subtask 5: 0 / 21
• Subtask 6: 0 / 29