Submission #344666

#	Time	Username	Problem	Language	Result	Execution time	Memory
344666		Nurlykhan	Bigger segments (IZhO19_segments)	C++17	73 / 100	1203 ms	262144 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;
const ll inf = (ll) 1e16 + 10;

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];

struct node {
    int l, r;
    pair<int, int> val;
    ll x;

    node() {
        l = r = -1;
        val = make_pair(0, 0);
    }
};

node t[N * 20];
int sz = 1;

void upd(ll x, pair<int, int> val, int v = 1, ll l = 0, ll r = inf) {
    if (l == r) {
        t[v].val = max(t[v].val, val);
        return;
    }
    ll m = (l + r) / 2;
    if (l <= x && x <= m) {
        if (t[v].l == -1) t[v].l = ++sz;
        assert(sz < 20 * N);
        upd(x, val, t[v].l, l, m);
    } else if (m + 1 <= x && x <= r) {
        if (t[v].r == -1) t[v].r = ++sz;
        assert(sz < 20 * N);
        upd(x, val, t[v].r, m + 1, r);
    }

    t[v].val = make_pair(0, 0);

    if (t[v].l != -1) t[v].val = max(t[v].val, t[t[v].l].val);
    if (t[v].r != -1) t[v].val = max(t[v].val, t[t[v].r].val);

}

pair<int, int> get(ll x, int v = 1, ll l = 0, ll r = inf) {
    if (l > x)
        return make_pair(0, 0);
   // cout << v << ' ' << l << ' ' << r << ' ' << x << endl;
    if (r <= x)
        return t[v].val;

    pair<int, int> ans = make_pair(0, 0);
    ll m = (l + r) / 2;
    if (t[v].l != -1) ans = max(ans, get(x, t[v].l, l, m));
    if (t[v].r != -1) ans = max(ans, get(x, t[v].r, m + 1, r));
    return ans;
}

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:74:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   74 |     scanf("%d", &n);
      |     ~~~~~^~~~~~~~~~
segments.cpp:76:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   76 |         scanf("%d", &a[i]);
      |         ~~~~~^~~~~~~~~~~~~

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