Submission #983125

#	Time	Username	Problem	Language	Result	Execution time	Memory
983125		_callmelucian	Split the sequence (APIO14_sequence)	C++14	100 / 100	722 ms	84428 KiB

sequence

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

typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> pl;
typedef pair<int,int> pii;
typedef tuple<int,int,int> tt;

#define all(a) a.begin(), a.end()
#define filter(a) a.erase(unique(all(a)), a.end())

ll divi (ll a, ll b) {
    return a / b + ((a ^ b) < 0 && a % b);
}

struct line {
    ll slope, c; int id;

    line (ll u = 0, ll v = 0, int z = 0) : slope(u), c(v), id(z) {}

    ll calc (ll x) { return slope * x + c; }

    friend ll isect (line a, line b) {
        return divi(a.c - b.c, b.slope - a.slope);
    }
};

struct CHT {
    deque<line> hull;

    void add (line cur) {
        while (hull.size() >= 2 && isect(hull[hull.size() - 2], hull.back()) > isect(hull.back(), cur))
            hull.pop_back();
        hull.push_back(cur);
    }

    pair<ll,int> query (ll x) {
        while (hull.size() >= 2 && x > isect(hull[0], hull[1]))
            hull.pop_front();
        return make_pair(hull.front().calc(x), hull.front().id);
    }
};

const int mn = 1e5 + 5;
ll dp[2][mn], pre[mn];
int trace[202][mn];

void track (int k, int i, vector<int> &cuts, vector<pl> &vec) {
    if (k == 0) {
        cuts.push_back(vec[i].second);
        return;
    }
    track(k - 1, trace[k][i], cuts, vec);
    cuts.push_back(vec[i].second);
}

int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);

    int n, split, cnt = 0; cin >> n >> split;
    vector<pl> vec(1);
    queue<int> zero;

    for (int i = 1; i <= n; i++) {
        int a; cin >> a;
        if (a) {
            vec.push_back(make_pair(a, i));
            cnt++;
        }
        else zero.push(i);
    }

    for (int i = 1; i <= cnt; i++)
        pre[i] = pre[i - 1] + vec[i].first;

    int use = min(split, cnt - 1);
    for (int k = 1; k <= use; k++) {
        int t = k & 1; CHT helper;
        for (int i = 1; i <= k; i++)
            helper.add(line(pre[i], dp[t ^ 1][i] - pre[i] * pre[i], i));
        for (int i = k + 1; i <= cnt; i++) {
            tie(dp[t][i], trace[k][i]) = helper.query(pre[i]);
            helper.add(line(pre[i], dp[t ^ 1][i] - pre[i] * pre[i], i));
        }
    }

    cout << dp[use & 1][cnt] << "\n";

    vector<int> cuts;
    track(min(split, cnt - 1), cnt, cuts, vec);
    cuts.pop_back();

    while (cuts.size() < split) {
        cuts.push_back(zero.front());
        zero.pop();
    }
    for (int u : cuts) cout << u << " ";

    return 0;
}

Compilation message (stderr)

sequence.cpp: In function 'int main()':
sequence.cpp:96:24: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   96 |     while (cuts.size() < split) {
      |            ~~~~~~~~~~~~^~~~~~~

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