Submission #802188

#	Time	Username	Problem	Language	Result	Execution time	Memory
802188		Johann	Mizuyokan 2 (JOI23_mizuyokan2)	C++14	0 / 100	459 ms	2360 KiB

mizuyokan2

#include "bits/stdc++.h"
using namespace std;

typedef long long ll;
typedef vector<ll> vi;
typedef vector<vi> vvi;
typedef pair<ll, ll> pii;
typedef vector<pii> vpii;
typedef vector<vpii> vvpii;
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()

const int INF = 1e9;

int N, Q;
vi L;

struct segtree
{
    vi arr;
    int size;
    void init(int _size)
    {
        size = 1;
        while (size < _size)
            size *= 2;
        arr.assign(2 * size, -INF);
    }
    void set(int i, ll v)
    {
        i += size;
        while (i > 0)
        {
            arr[i] = max(arr[i], v);
            i /= 2;
        }
    }
    ll query(int l, int r) { return query(l, r, 1, 0, size); }
    ll query(int l, int r, int x, int lx, int rx)
    {
        if (l <= lx && rx <= r)
            return arr[x];
        if (r <= lx || rx <= l)
            return -INF;
        int m = (lx + rx) / 2;
        return max(query(l, r, 2 * x, lx, m), query(l, r, 2 * x + 1, m, rx));
    }
};
segtree seg;

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);

    cin >> N;
    L.resize(N);
    for (int i = 0; i < N; ++i)
        cin >> L[i];
    cin >> Q;

    while (Q--)
    {
        ll x, y, a, b;
        cin >> x >> y >> a >> b;
        --x;
        L[x] = y;
        vi B(L.begin() + a, L.begin() + b);
        vi pref(sz(B));
        partial_sum(all(B), pref.begin());
        // starting with lower piece
        seg.init(sz(B));
        // seg used as dp
        // vi dp(sz(B), -INF); // dp[i] := number of zigzag pieces in prefix i with i as minimum
        vvpii activate(sz(B) + 1);

        seg.set(0, 1);
        for (int i = 1; i < sz(B); ++i)
        {
            for (pii tmp : activate[i])
                seg.set(tmp.first, tmp.second);

            ll needed;
            needed = pref[i - 1] - B[i] - 1;
            pii ac;
            if (needed < 0)
                ac = {i, 1};
            else
            {
                int r = upper_bound(all(pref), pref[i - 1] - B[i] - 1) - pref.begin();
                ac = {i, max(0LL, seg.query(0, r)) + 2};
            }
            needed = pref[i] + B[i] + 1;
            if (needed <= pref.back())
            {
                int idx = lower_bound(all(pref), needed) - pref.begin();
                if (idx < sz(activate))
                    activate[idx].push_back(ac);
            }
        }

        for (pii tmp : activate[sz(B)])
            seg.set(tmp.first, tmp.second);

        ll ans = seg.query(0, seg.size);
        ll buffer = 0;
        for (int i = sz(B) - 1; i > 0; --i)
        {
            buffer += B[i];
            if (buffer > B[i - 1])
                ans = max(ans, seg.arr[seg.size + i - 1] + 1);
        }

        cout << ans << "\n";
    }
}

• Subtask 1: 0 / 6
• Subtask 2: 0 / 9
• Subtask 3: 0 / 13
• Subtask 4: 0 / 32
• Subtask 5: 0 / 29
• Subtask 6: 0 / 11