Submission #853873

#	Time	Username	Problem	Language	Result	Execution time	Memory
853873		thanh913	Chase (CEOI17_chase)	C++14	100 / 100	188 ms	157496 KiB

chase

#include <bits/stdc++.h>
using namespace std;

#define fi first
#define se second
using ll = long long;

const int N = 1e5+5;

//--------------------------------------
int n, k, a[100001];
vector<int> adj[100001];
ll down[100001][101], up[100001][101], ans = 0;
 
void dfs(int u, int par) {
    ll sum = 0;
    for (int v : adj[u]) sum += a[v];
    up[u][1] = sum;
    for (int v : adj[u]) if (v != par) {
        dfs(v, u);
        for (int i = 1; i <= k; i++) ans = max(ans, up[u][i] + down[v][k - i]);
        for (int i = 1; i <= k; i++) {
            down[u][i] = max({down[u][i], down[v][i], down[v][i-1] + sum - a[par]});
            up[u][i] = max({up[u][i], up[v][i], up[v][i-1] + sum - a[v]});
        }
    }
    memset(up[u], 0, sizeof(up[u]));
    up[u][1] = sum;
    reverse(adj[u].begin(), adj[u].end());
    for (int v : adj[u]) if (v != par) {
        for (int i = 1; i <= k; i++) ans = max(ans, up[u][i] + down[v][k-i]);
        for (int i = 1; i <= k; i++)
            up[u][i] = max({up[u][i], up[v][i], up[v][i-1] + sum - a[v]});
    }
}
 
int main() {
    ios::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
    cin >> n >> k;
    for (int i = 1; i <= n; i++) cin >> a[i];
    for (int i = 1; i < n; i++) {
        int u, v; cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    dfs(1, 0);
    cout << ans;
}

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