Submission #598512

#	Time	Username	Problem	Language	Result	Execution time	Memory
598512		OttoTheDino	Chase (CEOI17_chase)	C++17	100 / 100	433 ms	491516 KiB

chase

#include <bits/stdc++.h>
using namespace std;
 
#define rep(i,s,e)                  for (ll i = s; i <= e; ++i)
#define rrep(i,s,e)                 for (ll i = s; i >= e; --i)
#define pb                          push_back
#define pf                          push_front
#define fi                          first
#define se                          second
#define all(a)                      a.begin(), a.end()
#define len(a)                      (ll)a.size()
typedef long long ll;
typedef pair<ll, ll> ii;
typedef pair<ll, ll> pll;
typedef vector<ii> vii;
typedef vector<ll> vi;
typedef vector<double> vd;
typedef vector<string> vs;
typedef vector<ll> vll;
 
const ll mx = 1e5, mxv = 100;
ll p[mx+1], s[mx+1], dpd[mx+1][mxv+1], dpu[mx+1][mxv+1], ans, l;
vi adj[mx+1];
 
void dfs (int u, int par) {
    pll dpd_nxt[mxv+1][2], dpu_here[mxv+1][2];

    rep (i,0,mxv) {
        if (i) {
            dpd[u][i] = s[u]-p[par];
            dpu[u][i] = s[u];
        }
        dpu_here[i][1] = dpd_nxt[i][0] = dpd_nxt[i][1] = {0,0};
        dpu_here[i][0] = {dpu[u][i],u};
    }

    for (int v : adj[u]) {
        if (v==par) continue;
        dfs (v, u);

        rep (i,0,mxv) {

            if (dpd[v][i]>=dpd_nxt[i][1].fi) dpd_nxt[i][1] = {dpd[v][i], v};

            if (dpd[v][i]>=dpd_nxt[i][0].fi) {
                dpd_nxt[i][1] = dpd_nxt[i][0];
                dpd_nxt[i][0] = {dpd[v][i], v};
            }

            dpd[u][i] = max(dpd[u][i], dpd[v][i]);
            if (i) {
                dpd[u][i] = max(dpd[u][i], s[u]-p[par]+dpd[v][i-1]);
                dpd[u][i] = max(dpd[u][i], dpd[u][i-1]);
            }
        }

        rep (i,0,mxv) {
            ll sth = i==0?dpu[v][i]:max(dpu[v][i], dpu[v][i-1]+s[u]-p[v]);

            if (sth>=dpu_here[i][1].fi) dpu_here[i][1] = {sth, v};

            if (sth>=dpu_here[i][0].fi) {
                dpu_here[i][1] = dpu_here[i][0];
                dpu_here[i][0] = {sth, v};
            }

            dpu[u][i] = max(dpu[u][i], sth);
            if (i) dpu[u][i] = max(dpu[u][i], dpu[u][i-1]);
        }
    }

    rep (i,0,l) {
        if (dpd_nxt[i][0].se==dpu_here[l-i][0].se) {
            ans = max(ans, dpd_nxt[i][0].fi+dpu_here[l-i][1].fi);
            ans = max(ans, dpd_nxt[i][1].fi+dpu_here[l-i][0].fi);
        }
        else ans = max(ans, dpd_nxt[i][0].fi+dpu_here[l-i][0].fi);
    }
}
 
int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
 
    ll n; cin >> n >> l;
 
    rep (i,1,n) cin >> p[i];
 
    rep (i,1,n-1) {
        ll u, v; cin >> u >> v;
        adj[u].pb(v);
        adj[v].pb(u);
    }
 
    rep (i,1,n) for (int v : adj[i]) s[i] += p[v];

    dfs (1,0);

    cout << ans << "\n";
 
    return 0;
}

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