Submission #344644

#	Time	Username	Problem	Language	Result	Execution time	Memory
344644		Nurlykhan	Bigger segments (IZhO19_segments)	C++17	13 / 100	2 ms	620 KiB

segments

#include <bits/stdc++.h>

#define ll long long

using namespace std;

const int N = (int)5e5 + 10;
const int mod = (int)1e9 + 7;

int n;
int a[N];
ll pref[N];

ll get_sum(int l, int r) {
    return pref[r] - pref[l - 1];
}

pair<int, int> dp[N];
unordered_map<int, pair<int, int> > t;

pair<int, int> get(ll x) {
    assert(x >= 0);
    pair<int, int> ans = make_pair(0, 0);
    while (x >= 0) {
        if (t.count(x))
            ans = max(ans, t[x]);
        x &= x + 1;
        x--;
    }
    return ans;
}

void upd(ll x, pair<int, int> y) {
    assert(x >= 0);
    while (x < (ll)1e15) {
        t[x] = max(t[x], y);
        x |= x + 1;
    }
}


int main() {
   // freopen("in.txt", "r", stdin);
    scanf("%d", &n);
    for (int i = 1; i <= n; i++) {
        scanf("%d", &a[i]);
        pref[i] = pref[i - 1] + a[i];
    }


    for (int i = 1; i <= n; i++) {
        dp[i] = make_pair(1, 1);
        dp[i] = max(dp[i], get(pref[i]));
        upd(2 * pref[i] - pref[dp[i].second - 1], make_pair(dp[i].first + 1, i + 1));
    }

    cout << dp[n].first;
    return 0;
}

Compilation message (stderr)

segments.cpp: In function 'int main()':
segments.cpp:44:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   44 |     scanf("%d", &n);
      |     ~~~~~^~~~~~~~~~
segments.cpp:46:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   46 |         scanf("%d", &a[i]);
      |         ~~~~~^~~~~~~~~~~~~

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