Submission #1296433

#	Time	Username	Problem	Language	Result	Execution time	Memory
1296433		idk_anything_i_guess	Split the sequence (APIO14_sequence)	C++20	0 / 100	1 ms	340 KiB

sequence

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

// -------------------- GLOBAL DATA --------------------
int n, k;
vector<ll> a, s;
vector<ll> dp_prev, dp_cur;
vector<vector<int>> parent;   // parent[t][i] = best split j for dp[t][i]

// compute dp_cur[l..r] using dp_prev and store parent[t][*]
void solve(int t, int l, int r, int optL, int optR) {
    if (l > r) return;
    int mid = (l + r) >> 1;

    pair<ll,int> best = {LLONG_MIN, -1};

    for (int j = optL; j <= min(mid-1, optR); j++) {
        ll val = dp_prev[j] + s[j] * (s[mid] - s[j]);
        if (val > best.first) {
            best = {val, j};
        }
    }

    dp_cur[mid] = best.first;
    parent[t][mid] = best.second;

    int opt = best.second;

    solve(t, l, mid - 1, optL, opt);
    solve(t, mid + 1, r, opt, optR);
}

// -------------------- MAIN --------------------
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    cin >> n >> k;

    a.assign(n+1, 0);
    s.assign(n+1, 0);

    for (int i = 1; i <= n; i++) cin >> a[i];
    for (int i = 1; i <= n; i++) s[i] = s[i-1] + a[i];

    dp_prev.assign(n+1, 0);
    dp_cur.assign(n+1, 0);

    // parent[t][i]
    parent.assign(k+1, vector<int>(n+1, -1));

    for (int t = 1; t <= k; t++) {
        solve(t, 1, n, 0, n-1);
        dp_prev = dp_cur;
    }

    ll answer = dp_prev[n];

    // -------------------- RECONSTRUCT SPLITS --------------------
    vector<int> cuts;
    int pos = n;
    for (int t = k; t >= 1; t--) {
        int j = parent[t][pos];
        cuts.push_back(j);
        pos = j;
    }
    reverse(cuts.begin(), cuts.end());

    // -------------------- OUTPUT --------------------
    cout << answer << "\n";
    for (int x : cuts) cout << x << " ";
    cout << "\n";
}

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