Submission #519104

#	Time	Username	Problem	Language	Result	Execution time	Memory
519104		Dasha_Gnedko	Bigger segments (IZhO19_segments)	C++17	0 / 100	8 ms	11980 KiB

segments

#include <bits/stdc++.h>

//#include <ext/pb_ds/detail/standard_policies.hpp>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>

//#pragma GCC optimize("Ofast")
//#pragma GCC target("avx2")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4")

using namespace std;

//using namespace __gnu_pbds;
//template <typename T> using ordered_set = tree <T, null_type, less < T >, rb_tree_tag, tree_order_statistics_node_update>;

mt19937 gen(time(0));

#define ll long long
#define ld long double
#define pb push_back
#define F first
#define S second
#define TIME clock() * 1.0 / CLOCKS_PER_SEC
#define sz(a) int32_t(a.size())
#define endl '\n'
//#define int long long

const int N = 5e5 + 100;
const int M = 31;
const int mod = 1e9 + 7;
const ll inf = 1e18 + 7;

ll pref[N];
vector < pair < int, ll > > add[N];
set < pair < int, ll > > st;
pair < int, ll > dp[N];

int32_t main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

#ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#else
//    freopen("input.txt", "r", stdin);
//    freopen("output.txt", "w", stdout);
#endif // LOCAL

    int n;
    cin >> n;
    int ans = 1; ll ls;
    for(int i = 0; i < n; i++)
    {
        int x;
        cin >> x;
        if (i) pref[i] = pref[i - 1];
        else ls = x;
        pref[i] += x;
    }
    add[0].pb({1, 0});
    for(int i = 0; i < n; i++)
    {
        for(auto to: add[i])
            st.insert(to);
        dp[i] = *st.rbegin();
        dp[i].S = pref[i] - dp[i].S;
        int l = i + 1, r = n - 1, gr = n;
        while (l <= r)
        {
            int mid = (l + r) / 2;
            ll cnt = pref[mid] - pref[i];
            if (cnt >= dp[i].S)
            {
                gr = mid;
                r = mid - 1;
            }
            else l = mid + 1;
        }
        add[gr].pb({dp[i].F + 1, dp[i].S});
    }
    cout << dp[n - 1].F;
}

Compilation message (stderr)

segments.cpp: In function 'int32_t main()':
segments.cpp:54:9: warning: unused variable 'ans' [-Wunused-variable]
   54 |     int ans = 1; ll ls;
      |         ^~~
segments.cpp:54:21: warning: variable 'ls' set but not used [-Wunused-but-set-variable]
   54 |     int ans = 1; ll ls;
      |                     ^~

• Subtask 1: 0 / 13
• Subtask 2: 0 / 14
• Subtask 3: 0 / 10
• Subtask 4: 0 / 36
• Subtask 5: 0 / 27