Submission #883784

#	Time	Username	Problem	Language	Result	Execution time	Memory
883784		dimashhh	Cat in a tree (BOI17_catinatree)	C++17	100 / 100	296 ms	244404 KiB

catinatree

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 2e5 + 1,MOD = 1e9 + 7;

struct ans{
    deque<int> dp;
    int sz(){
        return (int)dp.size();
    }
    ans():dp({1}){}    
};
ans x[N];
int n,d;
vector<int> g[N];
void merge(ans &a,ans &b){
    if(b.sz() > a.sz()){
        swap(a,b);
    }
    vector<int> combined_dp = vector<int> (b.dp.begin(),b.dp.end());
    for(int i = 0;i < (int)b.sz();i++){
        int t = d - i;
        if(t >= i){
            if(t < a.sz()) combined_dp[i] = max(combined_dp[i],b.dp[i] + a.dp[t]);
            if(t < b.sz()) combined_dp[i] = max(combined_dp[i],b.dp[t] + a.dp[i]);
        }else{
            combined_dp[i] = b.dp[i] + a.dp[i];
        }
    }
    int mx = 0;
    for(int i = b.sz() - 1;i >= 0;i--){
        mx = max(mx,combined_dp[i]);
        a.dp[i] = max(a.dp[i],mx);
    }
}
ans& dfs(int v){
    ans& f = x[v];
    for(int to:g[v]){
        ans &child = dfs(to);
        child.dp.push_front(child.dp.front());    
        merge(f,child);
    }
    return f;
}
void test(){
    cin >> n >> d;
    for(int i = 2;i <= n;i++){
        int x;
        cin >> x;
        ++x;
        g[x].push_back(i);
    }
    cout << dfs(1).dp[0];
}
int main(){
    ios_base::sync_with_stdio(0);cin.tie(0);
    int T = 1;
    // cin >> T;
    while(T--)  
        test();
}

• Subtask 1: 11 / 11
• Subtask 2: 40 / 40
• Subtask 3: 49 / 49