Submission #1045844

#	Time	Username	Problem	Language	Result	Execution time	Memory
1045844		phoenix0423	Chase (CEOI17_chase)	C++17	100 / 100	231 ms	345936 KiB

chase

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
#define fastio ios::sync_with_stdio(false), cin.tie(0)
// #pragma GCC optimize("Ofast")
#define pb push_back
#define eb emplace_back
#define f first
#define s second
#define int long long
#define lowbit(x) x&-x
const int maxn = 1e5 + 5;
const int INF = 4e18;
const int N = 998244353;
int dp[maxn][105][2][2];
vector<int> adj[maxn];
int p[maxn], deg[maxn];
int n, v, ans = 0;

void dfs(int pos, int prev){
    dp[pos][1][0][1] = deg[pos];
    dp[pos][1][1][1] = deg[pos] - p[pos];
    for(int i = 2; i <= v; i++) dp[pos][i][1][1] = dp[pos][i - 1][1][1];
    ans = max(ans, dp[pos][1][1][1]);
    for(auto x : adj[pos]){
        if(x == prev) continue;
        dfs(x, pos);
        for(int i = 1; i < v; i++){
            for(int j = 0; j < 2; j++){
                for(int k = 0; k < 2; k++){
                    ans = max(ans, dp[x][i][0][j] + dp[pos][v - i][1][k] - j * (p[x] + p[pos]));
                    ans = max(ans, dp[x][i][1][j] + dp[pos][v - i][0][k] - k * (p[x] + p[pos]));
                }
            }
        }
        for(int i = 1; i <= v; i++){
            for(int j = 0; j < 2; j++){
                for(int k = 0; k < 2; k++){
                    dp[pos][i][0][k] = max(dp[pos][i][0][k], dp[x][i - k][0][j] + (k ? deg[pos] : 0) - j * (p[x] + p[pos]));
                    dp[pos][i][1][k] = max(dp[pos][i][1][k], dp[x][i - k][1][j] + (k ? deg[pos] : 0) - k * (p[x] + p[pos]));
                }
            }
            for(int j = 0; j < 2; j++){
                for(int k = 0; k < 2; k++){
                    dp[pos][i][j][k] = max(dp[pos][i][j][k], dp[pos][i - 1][j][k]);
                }
            }
        }
    }
}

signed main(void){
    fastio;
    cin>>n>>v;
    for(int i = 0; i < n; i++) cin>>p[i], deg[i] += p[i];
    for(int i = 0; i < n - 1; i++){
        int a, b;   
        cin>>a>>b;
        a--, b--;
        adj[a].pb(b), adj[b].pb(a);
        deg[a] += p[b], deg[b] += p[a];
    }
    if(!v){
        cout<<0<<"\n";
        return 0;
    }
    dfs(0, -1);
    cout<<ans<<"\n";
}

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