数据结构与算法分析——c语言描述 练习4.30

挺有意思的。用了4.16练习的结论。递推与递归结合，生成一颗随机avl树

#include"fatal.h"
#include<stdlib.h>

typedef int ElementType;

struct AvlNode;
typedef struct AvlNode *Position;
typedef struct AvlNode *AvlTree;

struct AvlNode {
    ElementType element;
    AvlTree left;
    AvlTree right;
    int isDeleted;
    int height;
};

int RandInt(int i, int j) {
    int temp;
    temp = (int)(i + (1.0*rand() / RAND_MAX)*(j - i));
    return temp;
}

AvlTree makeRandomAVLTree(int H) {
    if (H >= 0) {
        AvlTree t = malloc(sizeof(struct AvlNode));
        if (t == NULL)
            Error("OUT OF MEMORY");
        t->left = makeRandomAVLTree(H - 1);
        t->right = makeRandomAVLTree(H - 2);

        if (t->left == NULL&&t->right == NULL) {
            t->element = rand();
        }
        else if (t->left == NULL)
            t->element = RandInt(0, t->right->element);
        else if (t->right == NULL)
            t->element = RandInt(t->left->element, RAND_MAX);
        else
            t->element = RandInt(t->left->element, t->right->element);

        return t;
    }
    return NULL;
}

void dir(AvlTree t) {
    if (t) {
        printf("%d ", t->element);
        dir(t->left);
        dir(t->right);
    }
}

int main() {
    AvlTree t = makeRandomAVLTree(9);
    dir(t);
}