C++中将信息传递到树中所有节点所需的最小迭代次数

#include<bits/stdc++.h>
using namespace std;

class Tree
{
   int nodes;
   list<int> *List_children;
   void Iteration(int vertices, int arr[]);

public:
   //constructor of a class
   Tree(int nodes);
   //method to insert a node in a tree
   void insert_node(int a, int b);
   //method to calculate the minimum iterations
   int Min_Iteration();
   static int check(const void *a_1, const void *b_1);
};

Tree::Tree(int nodes)
{
   this->nodes = nodes;
   List_children = new list<int>[nodes];
}
void Tree::insert_node(int a, int b)
{
   List_children[a].push_back(b);
}
void Tree::Iteration(int vertices, int arr[])
{
   arr[vertices] = List_children[vertices].size();
   int *ptr = new int[arr[vertices]];
   int temp = 0;
   int temp_2 = 0;
   list<int>::iterator it;

   for(it = List_children[vertices].begin(); it!= List_children[vertices].end(); ++it)
   {
      Iteration(*it, arr);
      ptr[temp++] = arr[*it];
   }

   qsort(ptr, arr[vertices], sizeof(int), check);

   for(temp = 0; temp < List_children[vertices].size(); temp++)
   {
      temp_2 = ptr[temp] + temp + 1;
      arr[vertices] = max(arr[vertices], temp_2);
   }
   delete[] ptr;
}
int Tree::Min_Iteration()
{
   int *ptr = new int[nodes];
   int temp = -1;

   for (int i = 0; i < nodes; i++)
   {
      ptr[i] = 0;
   }
   Iteration(0, ptr);
   temp = ptr[0];
   delete[] ptr;
   return temp;
}
int Tree::check(const void * a_1, const void * b_1)
{
}
int main()
{
   Tree T_1(8);
   T_1.insert_node(0, 1);
   T_1.insert_node(0, 3);
   T_1.insert_node(0, 4);
   T_1.insert_node(0, 6);
   T_1.insert_node(0, 2);
   T_1.insert_node(1, 7);
   T_1.insert_node(1, 2);
   T_1.insert_node(1, 3);
   T_1.insert_node(4, 6);
   T_1.insert_node(4, 7);
   cout<<"Minimum no. of iterations to pass information to all nodes in the tree are:"<<T_1.Min_Iteration();

   Tree T_2(2);
   T_2.insert_node(0, 1);
   cout<<"\nMinimum no. of iterations to pass information to all nodes in the tree are:" <<T_1.Min_Iteration();

   return 0;
}