UVA 12186 Another Crisis (tree dp)

The title is linked to
a very simple tree-shaped dp. The formula c=(k*t-1)/100+1 given in the book was very fascinating at first, but it was really wonderful afterwards.

#include<iostream>
#include<cstdio>
#include<cmath>
#include<vector>
#include<stack>
#include<string>
#include<algorithm>
#include<cstring>
#include<queue>
#define lk (k<<1)
#define rk (k<<1|1)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
const double pi=acos(-1.0);
const double eps=1e-8;
const double INF=1e20;
const int inf=0x3f3f3f3f;
const int N=1e5+10;
int n,t;
vector<int>son[N];
int dp(int p)
{
    
    
    if(son[p].empty()) return 1;
    vector<int>d;
    int k=son[p].size();
    for(int i=0;i<k;i++)
    {
    
    
        d.push_back(dp(son[p][i]));
    }
    sort(d.begin(),d.end());
    int c,ans=0;
    if((k*t)%100==0) c=k*t/100;
    else c=k*t/100+1;
    //c=(k*t-1)/100+1;
    for(int i=0;i<c;i++) ans+=d[i];
    return ans;
}
int main()
{
    
    
    while(scanf("%d%d",&n,&t)==2)
    {
    
    
        if(n==0&&t==0) break;
        int x;
        for(int i=0;i<=n;i++) son[i].clear();
        for(int i=1;i<=n;i++)
        {
    
    
            scanf("%d",&x);
            son[x].push_back(i);
        }
        printf("%d\n",dp(0));
    }
    return 0;
}