Submission #951654

#	Time	Username	Problem	Language	Result	Execution time	Memory
951654		qwe1rt1yuiop1	Fish 2 (JOI22_fish2)	C++14	8 / 100	17 ms	6468 KiB

fish2

#include <bits/stdc++.h>
#define int long long
// using ll = long long;
#define all(x) x.begin(), x.end()
#define sz(x) (int)x.size()
using namespace std;
using pii = pair<int, int>;

vector<int> ll, rr, v, p, ok;

void dfs(int x, int l, int r)
{
    ok[x] = 1;
    if (ll[x] != -1 && v[x] <= p[x - 1] - p[l - 1])
        dfs(ll[x], l, x - 1);
    if (rr[x] != -1 && v[x] <= p[r] - p[x])
        dfs(rr[x], x + 1, r);
}

void solve()
{
    int n;
    cin >> n;
    v.assign(n + 1, 0);
    for (int i = 1; i <= n; ++i)
        cin >> v[i];
    p = v;
    for (int i = 1; i <= n; ++i)
        p[i] += p[i - 1];
    v[0] = INT_MAX, v.emplace_back(INT_MAX);
    --v[0];

    vector<int> l(n + 2, -1), r(n + 2, -1);

    vector<int> stk;
    stk.emplace_back(0);
    for (int i = 1; i <= n; ++i)
    {
        while (v[stk.back()] < v[i])
            stk.pop_back();
        l[i] = stk.back();
        stk.emplace_back(i);
    }
    stk.clear();
    stk.emplace_back(n + 1);
    for (int i = n; i >= 1; --i)
    {
        while (v[stk.back()] <= v[i])
            stk.pop_back();
        r[i] = stk.back();
        stk.emplace_back(i);
    }

    ll.assign(n + 2, -1), rr = ll;

    for (int i = 1; i <= n; ++i)
    {
        if (v[l[i]] < v[r[i]])
        {
            assert(rr[l[i]] == -1);
            rr[l[i]] = i;
        }
        else
        {
            assert(ll[r[i]] == -1);
            ll[r[i]] = i;
        }
    }

    ok.assign(n + 1, 0);
    dfs(rr[0], 1, n);
    cout << accumulate(all(ok), 0) << '\n';
}

/*
 */

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

    solve();

    return 0;
}

• Subtask 1: 0 / 5
• Subtask 2: 8 / 8
• Subtask 3: 0 / 12
• Subtask 4: 0 / 23
• Subtask 5: 0 / 35
• Subtask 6: 0 / 17