生成N个节点随机二叉查找树的函数 具有从1到N的不同的关键字

数据结构与算法分析——c语言描述 练习4.29

本来想用一个长度为N的数组记录是否生成过这个随机数，然后在插入到树中。

看了作者的给的代码瞬间惊讶。还能这样做。

#include"fatal.h"#include<stdlib.h>typedef int ElementType;struct TreeNode;typedef struct TreeNode *Position;typedef struct TreeNode *SearchTree;struct TreeNode {ElementType element;SearchTree left;SearchTree right;};int RandInt(int i, int j) {int temp;temp = i + (1.0*rand() / RAND_MAX)*(j - i);return temp;}SearchTree makeRandomTree1(int lower, int upper) {if (lower <= upper) {SearchTree t;int randomNum = RandInt(lower, upper);t = malloc(sizeof(struct TreeNode));if (t == NULL)Error("OUT OF MEMORY");t->element = randomNum;t->left=makeRandomTree1(lower, randomNum - 1);t->right = makeRandomTree1(randomNum + 1, upper);return t;}return NULL;}SearchTree makeRandomTree(int n) {return makeRandomTree1(1, n);}void dir(SearchTree t) {if (t) {printf("%d ", t->element);dir(t->left);dir(t->right);}}int main() {SearchTree t = makeRandomTree(90);dir(t);}