二叉树-----创建

1.数组方法

#include <stdio.h>
#include<stdlib.h>
typedef struct node
{

	int value;
	struct node *pLeft;
	struct node *pRight;

}BinaryTree;

BinaryTree *ArrTree(int arr[], int length)
{
	BinaryTree *p = NULL;
	p = (BinaryTree*)malloc(sizeof(BinaryTree)*length);
	for (int i = 0;i < length;i++)
	{
		p[i].value = arr[i];
		p[i].pLeft = NULL;
		p[i].pRight = NULL;

	}
	for (int i = 0;i <= length / 2 - 1;i++)
	{
		if (2 * i + 1 <= length - 1)
			p[i].pLeft = &p[2 * i + 1];
		if (2 * i + 2 <= length - 1)
			p[i].pRight = &p[2 * i + 2];
	}
	return p;


}

int main()
{
	int a[] = { 1,2,3,4,5,6,7,8 };
	int len = sizeof(a)/sizeof(a[0]);
	BinaryTree *p = ArrTree(a, len);
	for (int i = 0;i < len;++i)
	{
		printf("%d %d %d ", p[i].value,p[i].pLeft->value,p[i].pRight->value);
		printf("\n");
	}
	return 0;
}