Submission #113066

#	Time	Username	Problem	Language	Result	Execution time	Memory
113066		dolphingarlic	Split the sequence (APIO14_sequence)	C++14	0 / 100	15 ms	4008 KiB

sequence

#include <bits/stdc++.h>
#pragma GCC optimize("O3")
#define FOR(i, x, y) for (int i = x; i < y; i++)
typedef long long ll;
using namespace std;

int n, k;
pair<int, int> dp[201][100001];
int pref[100001];

bool case1(int k, int l, int j, int i) {
    return (dp[i][k].first - dp[i][l].first >
            (pref[k] - pref[l]) * (pref[n] - pref[j]));
}

bool case2(int k, int l, int j, int i) {
    return ((dp[i][l].first - dp[i][k].first) * (pref[j] - pref[k]) >
            (dp[i][j].first - dp[i][k].first) * (pref[k] - pref[l]));
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cin >> n >> k;
    FOR(i, 1, n + 1) {
        int x;
        cin >> x;
        pref[i] = pref[i - 1] + x;
    }

    fill(dp[0], dp[0] + n + 1, make_pair(0, 0));
    FOR(i, 1, k + 1) {
        deque<int> q;
        q.push_back(0);
        dp[i][0] = {0, 0};
        FOR(j, 1, n + 1) {
            while (q.size() > 1 && case1(q[1], q[0], j, i - 1)) q.pop_front();

            int x = q[0];
            dp[i][j] = {dp[i - 1][x].first + (pref[j] - pref[x]) * (pref[n] - pref[j]), x};
            // cout << i << ' ' << j << ' ' << x << ' ' << dp[i][j].first << '\n';

            while (q.size() > 1 && case2(q[q.size() - 2], q[q.size() - 1], j, i - 1)) q.pop_back();
            q.push_back(j);
        }
    }

    int mx = 0, indx;
    FOR(i, 1, n + 1) {
        if (dp[k][i].first > mx) mx = dp[k][i].first, indx = i;
    }
    cout << mx << '\n';
    FOR(i, 0, k) {
        cout << indx << ' ';
        indx = dp[k - i][indx].second;
    }
    cout << '\n';
    return 0;
}

Compilation message (stderr)

sequence.cpp: In function 'int main()':
sequence.cpp:54:25: warning: 'indx' may be used uninitialized in this function [-Wmaybe-uninitialized]
         cout << indx << ' ';
                         ^~~

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