text: #pragma once
  #include<vector>
  #include<cmath>
  #include"graph_template.hpp"
  
  /**
   * @brief 部分木の大きさ
   */
  
  std::vector<int> child_size(int start,const graph& g){
  	std::vector<int>memo(g.size());
  	auto f=[&](auto f,int v,int p)->int{
  		T res=0;
  		for(auto t:g[v]){
  			if(t==p)continue;
  			res+=f(f,t,v);
  		}
  		return memo[v]=res+1;
  	};
  	f(f,start,-1);
  	return memo;
  }