Submission #161183

#	Time	Username	Problem	Language	Result	Execution time	Memory
161183		Minnakhmetov	Chase (CEOI17_chase)	C++14	100 / 100	757 ms	263216 KiB

chase

#include <bits/stdc++.h>
    
#define ll long long
#define all(aaa) aaa.begin(), aaa.end()
 
using namespace std;
 
const ll INF = 1e18;
const int N = 1e5 + 5, M = 105;
int a[N];
vector<int> g[N];
ll dp1[N][M], dp2[N][M][2], sum[N], dp3[M];
int n, m;
 
void upd(ll &a, ll b) {
    a = max(a, b);
}
 
ll ans = 0;
 
void dfs(int node, int anc) {
    if (anc != -1)
        g[node].erase(find(all(g[node]), anc));
    for (int to : g[node]) {
        sum[node] += a[to];
        dfs(to, node);
    }
 
    dp1[node][1] = sum[node];
    dp2[node][1][1] = sum[node];
    dp2[node][0][1] = -INF;
 
    ll up = (anc == -1 ? 0 : a[anc]);

    ans = max(ans, sum[node] + up);
 
    for (int k = 0; k < 2; k++) {
        memset(dp3, 0, sizeof(dp3));
 
        for (int to : g[node]) {
            for (int i = 0; i <= m; i++) {
                ll cur = dp3[m - i] + dp1[to][i];
                upd(ans, cur);
            }

            for (int i = 0; i <= m; i++) {
                for (int j = 0; j < 2; j++) {
                    ll cur = dp2[to][i][j] + (j ? a[node] : 0);
                    upd(dp3[i], cur);
                    if (i < m) {
                        upd(dp3[i + 1], sum[node] - a[to] + up + cur);
                    }
                }
            }
 
            for (int i = 1; i <= m; i++) {
                upd(dp3[i], dp3[i - 1]);
            }
        }
        reverse(all(g[node]));
    }
 
    for (int to : g[node]) {
        for (int i = 0; i <= m; i++) {
            upd(dp1[node][i], dp1[to][i]);
            if (i < m) {
                upd(dp1[node][i + 1] , dp1[to][i] + sum[node]);
                upd(ans, dp1[to][i] + sum[node] + up);
            }
            for (int j = 0; j < 2; j++) {
                ll cur = dp2[to][i][j] + (j ? a[node] : 0);
                upd(dp2[node][i][0], cur);
                if (i < m)
                    upd(dp2[node][i + 1][1], cur + sum[node] - a[to]);
            }
        }
    }
 
    for (int i = 1; i <= m; i++) {
        upd(dp2[node][i][0], dp2[node][i - 1][0]);
        upd(dp2[node][i][1], dp2[node][i - 1][1]);
        upd(dp1[node][i], dp1[node][i - 1]);
    }
 
    upd(ans, dp2[node][m][0]);
    upd(ans, dp2[node][m][1]);
    upd(ans, dp1[node][m]);
}
 
signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(NULL);
 
    cin >> n >> m;
 
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }
 
    for (int i = 0; i < n - 1; i++) {
        int a, b;
        cin >> a >> b;
        a--, b--;
        g[a].push_back(b);
        g[b].push_back(a);
    }

    if (m == 0) {
        cout << "0";
        return 0;
    }
 
    dfs(0, -1);
 
    cout << ans << "\n";
 
    return 0;
}

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