Submission #1099523

#	Time	Username	Problem	Language	Result	Execution time	Memory
1099523		steveonalex	Cat in a tree (BOI17_catinatree)	C++17	100 / 100	58 ms	25180 KiB

catinatree

#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
typedef unsigned long long ull;
 
#define MASK(i) (1LL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
#define ALL(v) (v).begin(), (v).end()
#define block_of_code if(true)
 
ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}
ll gcd(ll a, ll b){return __gcd(a, b);}
ll lcm(ll a, ll b){return a / gcd(a, b) * b;}
 
ll LASTBIT(ll mask){return (mask) & (-mask);}
int pop_cnt(ll mask){return __builtin_popcountll(mask);}
int ctz(ull mask){return __builtin_ctzll(mask);}
int logOf(ull mask){return 63 - __builtin_clzll(mask);}
 
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rngesus(ll l, ll r){return l + (ull) rng() % (r - l + 1);}
double rngesus_d(double l, double r){
    double cur = rngesus(0, MASK(60) - 1);
    cur /= MASK(60) - 1;
    return l + cur * (r - l);
}
 
template <class T1, class T2>
    bool maximize(T1 &a, T2 b){
        if (a < b) {a = b; return true;}
        return false;
    }
 
template <class T1, class T2>
    bool minimize(T1 &a, T2 b){
        if (a > b) {a = b; return true;}
        return false;
    }
 
template <class T>
    void printArr(T container, string separator = " ", string finish = "\n", ostream &out = cout){
        for(auto item: container) out << item << separator;
        out << finish;
    }
 
template <class T>
    void remove_dup(vector<T> &a){
        sort(ALL(a));
        a.resize(unique(ALL(a)) - a.begin());
    }

const int N = 2e5 + 69;
const int INF = 1e9 + 69;

int n, d;
vector<int> graph[N];
pair<int,int> dp[N];

void dfs(int u, int p){
    dp[u] = {1, 0};
    vector<pair<int, int>> children;
    int immature_cnt = 0;
    for(int v: graph[u]) if (v != p){
        dfs(v, u);
        dp[v].second++;
        if (dp[v].second < d) immature_cnt++;
        children.push_back(dp[v]);
    }
    if (immature_cnt == 0){
        for(pair<int, int> i: children) dp[u].first += i.first;
        return;
    }
    children.push_back(dp[u]);
    dp[u] = {0, INF};
    sort(ALL(children), [](pair<int, int> x, pair<int, int> y){return x.second < y.second;});
    while(children.size()){
        pair<int,int> v = children.back(); children.pop_back();
        if (dp[u].second + v.second >= d){
            dp[u].second = v.second;
            dp[u].first += v.first;
        }
        else dp[u].first += v.first - 1;
    }
}
 
int main(void){
    ios::sync_with_stdio(0);cin.tie(0); cout.tie(0);
    clock_t start = clock();

    cin >> n >> d;
    for(int i = 1; i<n; ++i){
        int p; cin >> p;
        graph[p].push_back(i);
        graph[i].push_back(p);
    }

    dfs(0, 0);

    cout << dp[0].first << "\n";

 
    cerr << "Time elapsed: " << clock() - start << " ms\n";
    return 0;
}

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