Submission #849269

#	Time	Username	Problem	Language	Result	Execution time	Memory
849269		Vu_CG_Coder	Cat in a tree (BOI17_catinatree)	C++14	51 / 100	35 ms	15312 KiB

catinatree

#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 100;
int n , d , res = 0;
vector <int> a[N];
int high[N], oder[N], value[N], par[N];

void dfs(int u){
    for (int v : a[u])
    if (v != par[u]){
        high[v] = high[u] + 1;
        par[v] = u;
        dfs(v);
    }
}

int get_min(int u){
    int val = 1e9 , x = 0;
    while (u != 0){
        val = min(val,value[u] + x);
        u = par[u], x++;
    }
    return val;
}

void update(int u){
    int val = 0; res++;
    while (u != 0){
        value[u] = min(value[u],val);
        u = par[u]; val++;
    }
}

bool cmp(int x ,int y){return high[x] > high[y];}
int main(){
    //freopen("txt.inp","r",stdin);
    //freopen("txt.out","w",stdout);
    cin >> n >> d;
    for (int i = 2; i <= n ; i++){
        int x; cin >> x; x++;
        a[x].push_back(i);
        a[i].push_back(x);
    }

    for (int i = 1 ; i < n ; i++){
        // int x , y;
        // cin >> x >> y;
        // a[x].push_back(y);
        // a[y].push_back(x);
        oder[i] = i;
    }
    oder[n] = n; par[1] = 0;
    dfs(1);
    sort(oder + 1,oder + n + 1,cmp);
    memset(value,0x3f,sizeof(value));
    for (int i = 1 ; i <= n ; i++)
        if (get_min(oder[i]) >= d) update(oder[i]);

    cout << res;
    return 0;
}

• Subtask 1: 11 / 11
• Subtask 2: 40 / 40
• Subtask 3: 0 / 49