Binary tree (8)----The number of nodes in the K-layer of the binary tree and the number of leaf nodes in the K-layer of the two-fork tree, the recursive method

1. Binary Tree definition

typedef struct BTREENODEELEMENT_T_ {    void *data;} btreenodeelement_t;typedef struct Btreenode_t_ {    btreenodeelement_t *m_pelemt;    struct Btreenode_t_    *m_pleft;    struct btreenode_t_    *m_pright;} btreenode_t;

2. Find the number of nodes in the K-layer of the binary tree

(1) Recursive method

Given root node Proot:

Returns 0 if Proot is empty, or if the number of layers Kthlevel <= 0, or if it is an empty tree or is not required;

If Proot is not empty and the layer kthlevel==1 at this point, then Proot is one of the K-tier nodes, then 1 is returned;

If Proot is not empty and the number of layers Kthlevel > 1, then the number of nodes in the Proot Zuozi (KthLevel-1) layer and Proot right subtree (KthLevel-1) layer nodes is required at this time;

int  getbtreekthlevelnodestotal (btreenode_t *proot, int kthlevel) {    if (proot = = NULL | | Kthlevel <= 0)        return 0;    if (proot! = NULL && Kthlevel = = 1)        return 1;    Return (Getbtreekthlevelnodestotal (Proot->m_pleft, KTHLEVEL-1) + getbtreekthlevelnodestotal (Proot->m_pright, KTHLEVEL-1));}

3, find the binary tree K-Layer leaf node points

(1) Recursive method

Given node Proot:

If Proot is empty, or if the number of layers Kthlevel <= 0, the empty tree or the number of layers is illegal, then 0 is returned;

If the proot is not empty, and if the number of layers is kthlevel==1, it is necessary to determine whether it is a leaf node:

If the Proot tree is empty, then the proot is one of the leaf nodes of the K-layer, then returns 1;

If one of the proot subtree is present, then the proot is not a leaf node, then 0 is returned;

If Proot is not empty, and the number of layers Kthlevel > 1, you need to return the Saozi right subtree node of the KTHLEVEL-1 layer.

int Getbtreekthlevelleafnodestotal (btreenode_t *proot, int kthlevel) {    if (proot = = NULL | | Kthlevel <= 0)        return 0;    if (proot! = null && Kthlevel = = 1) {        if (Proot->m_pleft = = NULL && Proot->m_pright = = null) 
   return 1;        else            return 0;    }    Return (Getbtreekthlevelleafnodestotal (  proot->m_pleft,  KthLevel-1) + getbtreekthlevelleafnodestotal ( Proot->m_pright, KthLevel-1));}

Binary tree (8)----The number of nodes in the K-layer of the binary tree and the number of leaf nodes in the K-layer of the two-fork tree, the recursive method