Submission #168054

#TimeUsernameProblemLanguageResultExecution timeMemory
168054Atill83Paprike (COI18_paprike)C++14
13 / 100
141 ms18740 KiB
#include <bits/stdc++.h>
#define ff first
#define ss second
#define endl '\n'
using namespace std;
const long long INF = (long long) 1e18;
const int mod = (int) 1e9+7;
const int MAXN = (int) 1e5+5;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
ll n, k;
vector<int> adj[MAXN];
ll hot[MAXN];
pll dfs(int a, int par){
    if(adj[a].size() == 1 && par != -1){
        return {0, hot[a]};
    }else{
        vector<pll> ans;
        ll eko = 0;
        for(int i: adj[a]){
            if(i != par){
                pll dat = dfs(i, a);
                eko += dat.ff;
                ans.push_back(dat);
            }
        }
        sort(ans.begin(), ans. end());
        ll cur = hot[a];
        int i = 0;
        for(; i < ans.size(); i++){
            if(cur + ans[i].ss > k){
                break;
            }else{
                cur = cur + ans[i].ss;
            }
        }
        return {eko + ans.size() - i, cur};
    }
}

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);cout.tie(nullptr);

    #ifdef Local
        freopen("../IO/int.txt","r",stdin);
        freopen("../IO/out.txt","w",stdout);
    #endif

    cin>>n>>k;
    for(int i = 1; i <= n; i++) cin>>hot[i];
    for(int i = 0; i < n - 1; i++){
        int a, b;
        cin>>a>>b;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    ll ans = INF;
    srand(time(NULL));
    for(int i = 0; i < 10; i++){
        ll a = rand()%n + 1;
        //cout<<a<<endl;
        ans = min(ans, dfs(a, -1).ff);
    }
    cout<<ans<<endl;

    #ifdef Local
        cout<<endl<<fixed<<setprecision(2)<<1000.0 * clock() / CLOCKS_PER_SEC<< " milliseconds ";
    #endif
}

Compilation message (stderr)

paprike.cpp: In function 'pll dfs(int, int)':
paprike.cpp:33:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(; i < ans.size(); i++){
               ~~^~~~~~~~~~~~
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