数据结构 - 二叉搜索树基本算法(c语言实现)

二叉搜索树基本算法：查找、删除一个节点、插入、找最大（最小）节点、中序遍历（前序和后序只要换个位置就好了）。

# include <stdio.h>
# include <stdlib.h>
// 建立节点模型
typedef struct TreeNode
{
    int data;
    struct TreeNode * left;
    struct TreeNode * right;
}SearchTree;

// 查找
SearchTree* search(SearchTree * T, int data)
{
    // 如果为空；
    if (T == NULL)
    {
        printf("此二叉树为空");
    }
    // 当不为空时分两种情况，第一种比此节点值大，第二种比此节点值小。
    else if (T->data > data)
    {
        return search(T->right,data);
    }
    else if (T->data < data)
    {
        return search(T->left, data);
    }
    else
    {
       return T;
    }
}
// 插入
SearchTree* insertTree(SearchTree * T, int data)
{
    // 如果为空
    if (T == NULL)
    {
        // 分配一块内存然后再挂在该树上
        T = (SearchTree *)malloc(sizeof(SearchTree));
        T->data = data;
        T->right = NULL;
        T->left = NULL;
        printf("%d插入树中\n",data);
        return T;
    }
    if (T->data > data)
    {
        T->left = insertTree(T->left, data);
    }
    else if (T->data < data)
    {
        T->right = insertTree(T->right, data);
    }
    else
        printf("%d已在树中，不能再次插入!!!\n",data);
    return T;
}
// 寻找树的最小节点
SearchTree* FindMin(SearchTree * T)
{
    if (T == NULL)
    {
        printf("该树为空");
    }
    if (T->left != NULL)
    {
        return FindMin(T->left);
    }
    return T;
}

// 寻找树的最大节点

SearchTree* findMax(SearchTree * T)
{
    if (T == NULL)
    {
        printf("该树为空");
    }
    if (T->right != NULL)
    {
        return FindMax(T->right);
    }
    return T->data;
}
// 删除
SearchTree* deleteTree(SearchTree * T, int data)
{
    if (T == NULL)
    {
        return T;
    }
    if (T->data > data)
    {
        T->left = deleteTree(T->left, data);
    }
    else if(T->data < data)
    {
        T->right = deleteTree(T->right, data);
    }
    // 找到该节点了
    else if (T->left != NULL && T->right != NULL)   // 该节点度为2
    {
        printf("该删除节点为%d\n", T->data);
        T->data = FindMin(T->right)->data;
        T->right = deleteTree(T->right,data);
    }
    else
    {
        printf("该删除节点为%d\n", T->data);
        T = (T->left != NULL)? T->left: T->right;
    }
    return T;
}
//中序输出:中序遍历二叉查找树可以得到原关键字有序序列
void print(SearchTree *  root)
{
    if(root!=NULL)
    {
        print(root->left);
        printf("%d ",root->data);
        print(root->right);
    }
 }
int main (void)
{
    int data[7] = {45,24,53,45,12,24,90};
    int i;
    SearchTree *  root = NULL; //二叉查找树根节点
    for(i=0;i<7;i++)    //创建二叉查找树
    {
        root = insertTree(root,data[i]);
    }
    print(root);
    printf("\n");
    root = insertTree(root, 55);
    print(root);
    printf("\n");
    root = deleteTree(root,24);
    print(root);
    printf("\n");
    return 0;
}

结果：

环境：code::blocks 13.12