BinSearchTree.c

#include <stdio.h>
#include <stdlib.h>

typedef int ElementType;
typedef struct TNode *Position;
typedef Position BinTree;
struct TNode{
	ElementType Data;
	BinTree Left;
	BinTree Right;
};

void PreorderTraversal( BinTree BT ); /* 先序遍历，由裁判实现，细节不表 */
void InorderTraversal( BinTree BT );  /* 中序遍历，由裁判实现，细节不表 */

BinTree Insert( BinTree BST, ElementType X );
BinTree Delete( BinTree BST, ElementType X );
Position Find( BinTree BST, ElementType X );
Position FindMin( BinTree BST );
Position FindMax( BinTree BST );

int main()
{
	BinTree BST, MinP, MaxP, Tmp;
	ElementType X;
	int N, i;

	BST = NULL;
	scanf("%d", &N);
	for ( i=0; i<N; i++ ) {
		scanf("%d", &X);
		BST = Insert(BST, X);
	}
	printf("Preorder:"); PreorderTraversal(BST); printf("\n");
	MinP = FindMin(BST);
	MaxP = FindMax(BST);
	scanf("%d", &N);
	for( i=0; i<N; i++ ) {
		scanf("%d", &X);
		Tmp = Find(BST, X);
		if (Tmp == NULL) printf("%d is not found\n", X);
		else {
			printf("%d is found\n", Tmp->Data);
			if (Tmp==MinP) printf("%d is the smallest key\n", Tmp->Data);
			if (Tmp==MaxP) printf("%d is the largest key\n", Tmp->Data);
		}
	}
	scanf("%d", &N);
	for( i=0; i<N; i++ ) {
		scanf("%d", &X);
		BST = Delete(BST, X);
	}
	printf("Inorder:"); InorderTraversal(BST); printf("\n");

	return 0;
}


BinTree Insert( BinTree BST, ElementType X ){
	if(BST==NULL){
		BST=(BinTree)malloc(sizeof(struct TNode));
		BST->Data=X;
		BST->Left=BST->Right=NULL;
	}
	else{
		if(X<BST->Data){
			BST->Left=Insert(BST->Left, X);
		}
		else{
			BST->Right=Insert(BST->Right, X);
		}
	}
	return BST;
}
Position FindMin( BinTree BST ){
	if(BST==NULL){
		return NULL;
	}
	if(BST->Left==NULL){
		return BST;
	}
	else{
		return FindMin(BST->Left);
	}
}
Position FindMax( BinTree BST ){
	if(BST==NULL){
		return NULL;
	}
	if(BST->Right==NULL){
		return BST;
	}
	else{
		return FindMax(BST->Right);
	}
}
BinTree Delete( BinTree BST, ElementType X ){
	if(BST==NULL){
		printf("Not Found\n");
		return NULL;
	}
	else 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&&BST->Right){
		BinTree temp=FindMin(BST->Right);
		BST->Data=temp->Data;
		BST->Right=Delete(BST->Right, temp->Data);
	}
	else{
		BinTree temp=BST;
		if(BST->Left==NULL){
			BST=BST->Right;
		}
		else{
			BST=BST->Left;
		}
		free(temp);
	}
	return BST;
}
Position Find( BinTree BST, ElementType X ){
	if(!BST){
		return NULL;
	}
	if(X<BST->Data){
		return Find(BST->Left, X);
	}
	else if(X>BST->Data){
		return Find(BST->Right, X);
	}
	else{
		return BST;
	}
}

void PreorderTraversal( BinTree BT ){
	if(BT){
		printf("%d ",BT->Data);
		PreorderTraversal(BT->Left);
		PreorderTraversal(BT->Right);
	}
}
void InorderTraversal( BinTree BT ){
	if(BT){
		InorderTraversal(BT->Left);
		printf("%d ",BT->Data);
		InorderTraversal(BT->Right);
	}
}