Submission #640586

#	Time	Username	Problem	Language	Result	Execution time	Memory
640586		CDuong	Paprike (COI18_paprike)	C++17	100 / 100	54 ms	18324 KiB

paprike

/*
#pragma GCC optimize("Ofast")
#pragma GCC target("avx2")
#pragma GCC optimize("unroll-loops")
*/
#include <bits/stdc++.h>
#define taskname "bai3"
#define int long long
#define ull unsigned long long
#define float long double
#define pb push_back
#define mp make_pair
#define ff first
#define ss second
#define endl '\n'
#define pii pair<int, int>
using namespace std;
const int mxN = 1e5 + 5;
const int mod = 1e9 + 7;
const int oo = 0x3f3f3f3f;
int n, k, val[mxN], sus[mxN];
vector<int> G[mxN];
int ans;
int sum(int u, int par){
    int res = val[u];
    for(auto tmp : G[u]){
        //cout << u << " " << tmp << endl;
        if(tmp == par) continue;
        res += sum(tmp, u);
    }
    if(res > k){
        vector<int> v;
        for(auto tmp : G[u]){
            if(tmp == par) continue;
            v.pb(sus[tmp]);
        }
        //cout << v.size() << endl;
        sort(v.begin(), v.end());
        int sums = val[u];
        for(int i = 0; i < (int)v.size(); ++i){
            if(sums + v[i] <= k) sums += v[i];
            else{
                ans += v.size() - i;
                sus[u] = sums;
                return sus[u];
            }
        }
    }
    //cout << u << " " << res << endl;
    sus[u] = res;
    return res;
}
void solve(){
    cin >> n >> k;
    for(int i = 1; i <= n; ++i){
        cin >> val[i];
    }
    for(int i = 1; i < n; ++i){
        int x, y; cin >> x >> y;
        //cout << x << " " << y << endl;
        G[x].pb(y);
        G[y].pb(x);
    }
    sum(1, -1);
    cout << ans << endl;
}
signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    //freopen(taskname".inp", "r", stdin);
    //freopen(taskname".out", "w", stdout);
    int t = 1; //cin >> t;
    while(t--) solve();
}

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