Submission #1127763

#	Time	Username	Problem	Language	Result	Execution time	Memory
1127763		VMaksimoski008	Bigger segments (IZhO19_segments)	C++17	100 / 100	216 ms	14116 KiB

segments

#include <bits/stdc++.h>
#define ar array
//#define int long long

using namespace std;

using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;

const int mod = 1e9 + 7;
const int LOG = 20;
const int maxn = 1e5 + 5;

struct fenwick {
    int n;
    vector<pii> tree;

    fenwick(int _n) : n(_n+10), tree(_n+50) {}

    void update(int p, int v, int p2) {
        for(p++; p<n; p+=p&-p) tree[p] = max(tree[p], { v, p2 });
    }

    pii query(int p) {
        pii ans = { 0, 0 };
        for(p++; p; p-=p&-p) ans = max(ans, tree[p]);
        return ans;
    }
};

signed main() {
    int n; cin >> n;
    vector<int> a(n+1);
    vector<ll> pref(n+1);
    for(int i=1; i<=n; i++) cin >> a[i];
    for(int i=1; i<=n; i++) pref[i] = pref[i-1] + a[i];
    pref.push_back(1e18);

    vector<int> dp(n+1), last(n+1);
    dp[0] = 0;

    fenwick fwt(n);
    for(int i=1; i<=n; i++) {
        auto [v, p] = fwt.query(i);
        dp[i] = v + 1;
        last[i] = p;
        ll V = 2 * pref[i] - pref[p];
        int l=0, r=n+1, pos=0;
        while(l <= r) {
            int mid = (l + r) / 2;
            if(V <= pref[mid]) pos = mid, r = mid - 1;
            else l = mid + 1;
        }
        fwt.update(pos, dp[i], i);
    }

    cout << dp[n] << '\n';
    return 0;
}

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