Submission #173470

#	Time	Username	Problem	Language	Result	Execution time	Memory
173470		emil_physmath	Bigger segments (IZhO19_segments)	C++17	100 / 100	125 ms	18680 KiB

segments

#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;
typedef double ldouble;
typedef long long llong;
typedef unsigned int uint;
typedef pair<int, llong> Dp;

template<typename T1, typename T2>
inline ostream& operator<<(ostream& str, const pair<T1, T2>& p)
{
    return str << "{" << p.first << ", " << p.second << "}";
}
inline const Dp& BestDp(const Dp& a, const Dp& b)
{
    if (a.first == b.first) return a.second < b.second ? a : b;
    return a.first > b.first ? a : b;
}
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    int n;
    cin >> n;
    vector<int> a(n);
    for (int& x: a)
        cin >> x;
    vector<llong> pref(n);
    for (int i = 0; i < n; ++i)
        pref[i] = a[i] + (i ? pref[i - 1] : 0);
    vector<Dp> dp(n);
    for (int i = 0; i < n; ++i)
        dp[i] = {1, pref[i]};
    for (int i = 0; i + 1 < n; ++i)
    {
        dp[i + 1] = BestDp(dp[i + 1], {dp[i].first, dp[i].second + a[i + 1]});
        int j = -1;
        int l = i + 1, r = n - 1;
        while (l <= r)
        {
            int m = (l + r) / 2;
            if (pref[m] - pref[i] >= dp[i].second)
            {
                j = m;
                r = m - 1;
            }
            else
                l = m + 1;
        }
        if (j != -1)
        {
            dp[j] = BestDp(dp[j], {dp[i].first + 1, pref[j] - pref[i]});
            // cerr << "i: " << i << "; " << "j: " << j << "\t" << dp[j] << endl;
        }
    }
    /*for (int i = 0; i < dp.size(); ++i)
        cerr << "dp[" << i << "] = " << dp[i] << endl;*/
    cout << max_element(dp.begin(), dp.end())->first << endl;
}

• Subtask 1: 13 / 13
• Subtask 2: 14 / 14
• Subtask 3: 10 / 10
• Subtask 4: 36 / 36
• Subtask 5: 27 / 27