二叉树的操作

• 题目描述

　　http://dsalgo.openjudge.cn/binarytree/10/

• 代码

  #include <iostream>
  using namespace std;
  #define  MAX_MN 105
  struct Node
  {
      int parent,lchild,rchild;
  };
  
  struct Node nodes[MAX_MN];
  
  void setRelation(int parent,int from,int to)
  {
      if (nodes[parent].lchild == from)
      {
          nodes[parent].lchild  = to;
      }else if (nodes[parent].rchild == from)
      {
          nodes[parent].rchild  = to;
      }else{
          cout<<"error";
      }
      nodes[to].parent = parent;
  }
  void swapNode(int l,int r)
  {
      int lp = nodes[l].parent;
      int rp =  nodes[r].parent;
      if(l == r)
      {
          return ;
      }else if (lp == rp)
      {
          //交换父亲的左右孩子指针
          //原来代码：
  
          /************************************************************************/
          /* 
          nodes[lp].lchild = l;
          nodes[lp].rchild = r;
          l 不一定就是父亲对应的左孩子
          */
          /************************************************************************/
          int temp;
          temp = nodes[lp].lchild;
          nodes[lp].lchild = nodes[lp].rchild;
          nodes[lp].rchild = temp;
          return;
      }
      setRelation(lp,l,r);
      setRelation(rp,r,l);
  }
  void askNode(int i)
  {
      int c = i;
      while(nodes[c].lchild != -1)
      {
          c = nodes[c].lchild;
      }
      cout<<c<<endl;
  }
  int main()
  {
      int t,m,n;
      int p,l,r,op;
      cin>>t;
  
      for (int tc = 0;tc <t;tc++)
      {
          cin>>n>>m;
          for (int i=0;i<MAX_MN;i++)
          {
              nodes[i].parent = -1;
              nodes[i].lchild = -1;
              nodes[i].rchild = -1;
          }
          for (int i=0;i<n;i++)
          {
              cin>>p>>l>>r;
              nodes[p].lchild = l;
              nodes[p].rchild = r;
              if (l != -1)
              {
                  nodes[l].parent = p;
              }
              if (r != -1)
              {
                  nodes[r].parent = p;
              }
          }
          for (int i=0;i<m;i++)
          {
              cin>>op;
              if (op == 1)
              {
                  cin>>l>>r;
                  swapNode(l,r);
              }else if (op == 2)
              {
                  cin>>l;
                  askNode(l);
              }
          }
      }
      return 0;
  }