Submission #939086

#	Time	Username	Problem	Language	Result	Execution time	Memory
939086		Alihan_8	Chase (CEOI17_chase)	C++17	0 / 100	280 ms	524288 KiB

chase

#include <bits/stdc++.h>

using namespace std;

#define all(x) x.begin(), x.end()
#define ar array
#define pb push_back
#define ln '\n'
//#define int long long

using i64 = long long;

template <class F, class _S>
bool chmin(F &u, const _S &v){
    bool flag = false;
    if ( u > v ){
        u = v; flag |= true;
    }
    return flag;
}

template <class F, class _S>
bool chmax(F &u, const _S &v){
    bool flag = false;
    if ( u < v ){
        u = v; flag |= true;
    }
    return flag;
}

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

    int n, k; cin >> n >> k;
    vector <int> a(n);
    for ( auto &u: a ) cin >> u;
    vector <vector<int>> G(n);
    for ( int i = 0; i + 1 < n; i++ ){
        int u, v; cin >> u >> v;
        --u, --v;
        G[u].pb(v), G[v].pb(u);
    }
    vector <int> s(n);
    for ( int i = 0; i < n; i++ ){
        for ( auto &v: G[i] ){
            s[i] += a[v];
        }
    }
    vector <vector<multiset<int>>> dp(n, vector <multiset<int>> (k + 1));
    for ( int i = 0; i < n; i++ ){
        for ( int j = 0; j <= k; j++ ){
            dp[i][j].insert(0);
        }
    }
    auto er = [&](auto &s, int u){
        s.erase(s.find(u));
    };
    auto get = [&](int v, int j, int u){
        return max(*dp[v][j].rbegin(), (j > 0 ? *dp[v][j - 1].rbegin() + s[v] - a[u] : 0));
    };
    auto dfs = [&](auto dfs, int u, int p) -> void{
        for ( auto &v: G[u] ){
            if ( v != p ){
                dfs(dfs, v, u);
                for ( int j = 0; j <= k; j++ ){
                    dp[u][j].insert(get(v, j, u));
                }
            }
        }
    };
    dfs(dfs, 0, -1);
    int opt = 0;
    auto dfs2 = [&](auto dfs2, int u, int p) -> void{
        for ( int j = 1; j <= k; j++ ){
            chmax(opt, *dp[u][j - 1].rbegin() + s[u]);
        }
        if ( n > 1e3 ) return;
        for ( auto &v: G[u] ){
            if ( v == p ) continue;
            for ( int j = 0; j <= k; j++ ){
                er(dp[u][j], get(v, j, u));
            }
            for ( int j = 0; j <= k; j++ ){
                dp[v][j].insert(get(u, j, v));
            }
            dfs2(dfs2, v, u);
            for ( int j = 0; j <= k; j++ ){
                er(dp[v][j], get(u, j, v));
            }
            for ( int j = 0; j <= k; j++ ){
                dp[u][j].insert(get(v, j, u));
            }
        }
    };
    dfs2(dfs2, 0, -1);
    cout << opt;

    cout << '\n';
}

/*
12 2
2 3 3 8 1 5 6 7 8 3 5 4
2 1
2 7
3 4
4 7
7 6
5 6
6 8
6 9
7 10
10 11
10 12

5 2
3 1 2 4 1
5 2
1 2
2 3
3 4
*/

• Subtask 1: 0 / 20
• Subtask 2: 0 / 20
• Subtask 3: 0 / 30
• Subtask 4: 0 / 30