Submission #240754

#	Time	Username	Problem	Language	Result	Execution time	Memory
240754		kartel	Paprike (COI18_paprike)	C++14	100 / 100	79 ms	20728 KiB

paprike

#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
#define in(x) freopen(x, "r", stdin)
#define out(x) freopen(x, "w", stdout)
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("-O3")
#define F first
#define S second
#define pb push_back
#define N +200500
#define M ll(1e9 + 7)
#define sz(x) (int)x.size()
#define re return
#define oo ll(1e9)
#define el '\n'
#define pii pair <int, int>
#define err ld(1e-9)
#define last(x) x.back()
#define all(x) (x.begin(), x.end())
using namespace std;
//using namespace __gnu_pbds;
//typedef tree <int, null_type, less_equal <int> , rb_tree_tag, tree_order_statistics_node_update> ordered_set;
typedef long long ll;
typedef long double ld;

vector <int> g[N];
ll f[N], cost[N], k;
int i, n, u, v, ans;

bool cmp(int u, int v)
{
    return f[u] < f[v];
}

void dfs(int v, int pr)
{
    vector <int> vec;
    f[v] = cost[v];

    for (auto u : g[v])
    {
        if (u == pr) continue;

        dfs(u, v);

        f[v] += f[u];

        vec.pb(u);
    }

    if (f[v] > k)
    {
        sort(vec.begin(), vec.end(), cmp);

//        cerr << el;
//        for (auto x : vec) cerr << x << " " << f[x] << el;

        while (f[v] > k)
        {
//            cerr << v << " " << vec.back() << el;
            f[v] -= f[vec.back()];
            vec.pop_back();
            ans++;
        }
    }
//    cerr << v << " " << f[v] << el;
//    cerr << el;
}

int main()
{
    srand(time(0));
    ios_base::sync_with_stdio(0);
    iostream::sync_with_stdio(0);
    ios::sync_with_stdio(0);
    cin.tie(NULL);
    cout.tie(NULL);

//    in("input.txt");
//    out("output.txt");

    cin >> n >> k;

    for (i = 1; i <= n; i++) cin >> cost[i];

    for (i = 1; i < n; i++)
    {
        cin >> u >> v;

        g[u].pb(v);
        g[v].pb(u);
    }

    dfs(1, -1);

    cout << ans;
}

//
//00000
//00110
//00111
//00011
//00000

• Subtask 1: 11 / 11
• Subtask 2: 13 / 13
• Subtask 3: 27 / 27
• Subtask 4: 49 / 49