Submission #1313786

#	Time	Username	Problem	Language	Result	Execution time	Memory
1313786		Zbyszek99	Chase (CEOI17_chase)	C++20	100 / 100	323 ms	329196 KiB

chase

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define ll long long
#define ld long double
#define ull unsigned long long
#define ff first
#define ss second
#define pii pair<int,int>
#define pll pair<long long, long long>
#define vi vector<int>
#define vl vector<long long>
#define pb push_back
#define rep(i, b) for(int i = 0; i < (b); ++i)
#define rep2(i,a,b) for(int i = a; i <= (b); ++i)
#define rep3(i,a,b,c) for(int i = a; i <= (b); i+=c)
#define count_bits(x) __builtin_popcountll((x))
#define all(x) (x).begin(),(x).end()
#define siz(x) (int)(x).size()
#define forall(it,x) for(auto& it:(x))
using namespace __gnu_pbds;
using namespace std;
typedef tree<int, null_type, less<int>, rb_tree_tag,tree_order_statistics_node_update> ordered_set;
//mt19937 mt;void random_start(){mt.seed(chrono::time_point_cast<chrono::milliseconds>(chrono::high_resolution_clock::now()).time_since_epoch().count());}
//ll los(ll a, ll b) {return a + (mt() % (b-a+1));}
const int INF = 1e9+50;
const ll INF_L = 1e18+40;
const ll MOD = 1e9+7;

vi graph[100001];
ll dp[100001][101];
ll old_dp[100001][101];
pll best[100001][101];
ll p[100001];
ll ans;
int n,k;

void dfs_first(int v, int pop)
{
    ll sum = 0;
    rep2(i,0,k) dp[v][i] = 0;
    forall(it,graph[v])
    {
        if(it != pop)
        {
            dfs_first(it,v);
            sum += p[it];
            rep2(i,0,k) dp[v][i] = max(dp[v][i],dp[it][i]);
        }
    }
    for(int i = k; i >= 1; i--) dp[v][i] = max(dp[v][i],dp[v][i-1]+sum);
}

void dfs_reroot(int v, int pop)
{
    ll sum = 0;
    rep2(i,0,k) old_dp[v][i] = dp[v][i];
    rep2(i,0,k) dp[v][i] = 0;
    rep2(i,0,k) best[v][i] = {0,0};
    forall(it,graph[v])
    {
        sum += p[it];
        rep2(i,0,k) 
        {
            dp[v][i] = max(dp[v][i],dp[it][i]);
            if(dp[it][i] > best[v][i].ff)
            {
                swap(best[v][i].ff,best[v][i].ss);
                best[v][i].ff = dp[it][i];
            }
            else if(dp[it][i] > best[v][i].ss)
            {
                best[v][i].ss = dp[it][i];
            }
        }
    } 
    rep2(i,0,k) ans = max(ans,dp[v][i]);
    rep2(i,1,k) ans = max(ans,dp[v][i-1]+sum);
    forall(it,graph[v])
    {
        if(it == pop) continue;
        rep2(i,0,k)
        {
            if(dp[it][i] == best[v][i].ff) dp[v][i] = best[v][i].ss;
            else dp[v][i] = best[v][i].ff;
        }
        for(int i = k; i >= 1; i--) dp[v][i] = max(dp[v][i],dp[v][i-1]+sum-p[it]);
        dfs_reroot(it,v);
    }
    rep2(i,0,k) dp[v][i] = old_dp[v][i];
}

int main()
{
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    //random_start();
    cin >> n >> k;
    rep2(i,1,n) cin >> p[i];
    rep(i,n-1)
    {
        int a,b;
        cin >> a >> b;
        graph[a].pb(b);
        graph[b].pb(a);
    }
    dfs_first(1,1);
    dfs_reroot(1,1);
    cout << ans << "\n";
}

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 30 / 30
• Subtask 4: 30 / 30