Submission #853540

#	Time	Username	Problem	Language	Result	Execution time	Memory
853540		thanh913	Chase (CEOI17_chase)	C++14	40 / 100	3721 ms	174908 KiB

chase

#include <bits/stdc++.h>
using namespace std;
 
#define fi first
#define se second
using ll = long long;
 
const int N = 1e5+5;
 
template<class X, class Y>
bool cmax(X &a, const Y &b) {
    return a < b ? a = b, 1 : 0;
}
 
//--------------------------------------
int n, k, a[N];
vector<int> adj[N];

ll f[N][105][2];
void dfs(int u, int pr) {
    ll s = 0;
    for (auto v : adj[u]) if (v != pr) {
        dfs(v, u);
        s += a[v];
    }
 
    f[u][0][0] = 0; f[u][1][1] = s;
    for (auto v : adj[u]) if (v != pr) {
        for (int i = 0; i <= k; i++) {
            cmax(f[u][i][0], max(f[v][i][0], f[v][i][1] + a[u]));
            if (i) {
                cmax(f[u][i][1], f[v][i-1][0] + s - a[v]);
                cmax(f[u][i][1], f[v][i-1][1] + s - a[v] + a[u]);
            }
        }
    }
}

const clock_t begin_time = clock();

double getTime() {
    return (((double)(clock() - begin_time)) / CLOCKS_PER_SEC);
}

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

ll getInt(ll l, ll r) {
    return l + rng() % (r-l+1);
}
 
int main() {
    ios::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
    vector<int> nodes;
    cin >> n >> k;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        nodes.push_back(i);
    }
    for (int i = 1; i < n; i++) {
        int u, v; cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }

    shuffle(nodes.begin(), nodes.end(), rng);
    ll ans = 0;
    for (auto root : nodes) { // doi
        if (getTime() > 3.7) break;
        for (int i = 1; i <= n; i++) {
            memset(f[i], -63, sizeof(f[i]));
        }
        dfs(root, root);
        
        for (int i = 0; i <= k; i++) {
            cmax(ans, max(f[root][i][0], f[root][i][1]));
        }
    }
    cout << ans;
}

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