PTA 6-12 (二叉树的递归删除)

 BinTree Insert( BinTree BST, ElementType X )
 {
     if (BST==NULL) {
         BinTree tmp=(BinTree)malloc(sizeof(struct TNode));
         tmp->Data=X;
         tmp->Left=tmp->Right=NULL;
         return tmp;
     };
     if (X<BST->Data)
         BST->Left=Insert(BST->Left,X);
     else
         BST->Right=Insert(BST->Right,X);
     return BST;
 }

 Position Find( BinTree BST, ElementType X ) {
     if (BST==NULL||BST->Data==X)  return BST;
     if (X<BST->Data)  return Find (BST->Left,X);
     else              return Find (BST->Right,X);
 }

 Position FindMin( BinTree BST ) {
     if (BST==NULL||BST->Left==NULL) return BST;
     else                            return FindMin (BST->Left);
 }

 Position FindMax( BinTree BST ) {
     if (BST==NULL||BST->Right==NULL) return BST;
     else                             return FindMax (BST->Right);
 }

 BinTree Delete( BinTree BST, ElementType X ) {
     BinTree TMP;
     if (BST==NULL) {
         printf ("Not Found\n");
         return NULL;
     }
     if (X<BST->Data)
         BST->Left=Delete (BST->Left,X);
     else  if (X>BST->Data)
         BST->Right=Delete (BST->Right,X);
     else {
         if (BST->Left!=NULL&&BST->Right!=NULL)  {
             TMP=FindMin (BST->Right);
             BST->Data=TMP->Data;
             BST->Right=Delete (BST->Right,TMP->Data);
         }
         else {
             TMP=BST;
             if (BST->Left!=NULL)
                 BST=BST->Left;
             else if (BST->Right!=NULL)
                 BST=BST->Right;
             else BST=NULL;
         }
     }
     return BST;
 }