Submission #735303

#	Time	Username	Problem	Language	Result	Execution time	Memory
735303		DrearyJoke	Paprike (COI18_paprike)	C++17	100 / 100	57 ms	24224 KiB

paprike

#include<bits/stdc++.h>

using namespace std;

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

#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define END "\n"
#define rall(v) (v).rbegin(), (v).rend()
#define all(v) (v).begin(), (v).end()
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
#include <ext/pb_ds/assoc_container.hpp>

using namespace __gnu_pbds;
template <typename T>
using ordered_set =
    tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

void solve(){
    int n, k;
    cin >> n >> k;
    vector<ll> A(n);
    for (int i = 0; i < n; ++i) cin >> A[i];
    vector<vector<int>> adj(n);
    for (int i = 0; i < n - 1; ++i) {
        int a, b;
        cin >> a >> b;
        --a, --b;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    vector<ll> sum(n), dp(n);
    auto dfs = [&] (auto&& self, int v, int p) -> void {
        sum[v] += A[v];
        for (auto u: adj[v]) {
            if (u != p) {
                self(self, u, v);
                dp[v] += dp[u];
                sum[v] += sum[u];
            }
        }
        if (sum[v] <= k) return;
        vector<int> idxes;
        for (auto u: adj[v]) {
            if (u != p) idxes.push_back(u);
        }
        sort(all(idxes), [&] (int a, int b) {
            return sum[a] > sum[b];
        });
        for (auto u: idxes) {
            sum[v] -= sum[u];
            ++dp[v];
            if (sum[v] <= k) break;
        }
    };
    dfs(dfs, 0, -1);
    cout << dp[0] << END;
}
int main()
{
    fastio
    int t = 1;
    // cin>> t;
    while(t--) solve();
    return 0;
}

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