二叉排序树

题目

题目描述：    输入一系列整数，建立二叉排序数，并进行前序，中序，后序遍历。输入：    输入第一行包括一个整数n(1<=n<=100)。    接下来的一行包括n个整数。输出：    可能有多组测试数据，对于每组数据，将题目所给数据建立一个二叉排序树，并对二叉排序树进行前序、中序和后序遍历。    每种遍历结果输出一行。每行最后一个数据之后有一个空格。样例输入：51 6 5 9 8样例输出：1 6 5 9 8 1 5 6 8 9 5 8 9 6 1 提示：输入中可能有重复元素，但是输出的二叉树遍历序列中重复元素不用输出。

AC代码

#include <stdio.h>#include <stdlib.h>#include <string.h> #define N 101 struct btree{    struct btree *lchild, *rchild;    int data;}; struct stack{    struct btree* arr[N];    int top;}; struct btree* create_sortree(struct btree* t, int d);void pre_traverse(struct btree *t);void order_traverse(struct btree *t);void post_traverse(struct btree *t);void clean_tree(struct btree *t); int main(){    int i, n, d;    struct btree *t;    while (scanf("%d", &n) != EOF) {        //接收客户端输入，构建二叉排序树        for (i = 0, t = NULL; i < n; i ++) {            scanf("%d", &d);            t = create_sortree(t, d);        }                 // 前序遍历        pre_traverse(t);         // 中序遍历        order_traverse(t);         // 后序遍历        post_traverse(t);         // 清理        clean_tree(t);    }     return 0;}   struct btree* create_sortree(struct btree *t, int d){    if (t == NULL) {        t = (struct btree*)malloc(sizeof(struct btree) * 1);        t->data = d;        t->lchild = NULL;        t->rchild = NULL;    }else if(t->data > d) {   // 插入到左子树        t->lchild = create_sortree(t->lchild, d);    }else if(t->data < d) { // 插入到右子树        t->rchild = create_sortree(t->rchild, d);    }else {        // 相同元素不进行任何操作    }     return t;} void pre_traverse(struct btree *t){    struct btree *p = t;    struct stack *s = (struct stack*)malloc(sizeof(struct stack) * 1);    s->top = 0;     while (s->top || p) {        if (p) {            printf("%d ", p->data);            s->arr[s->top ++] = p;            p = p->lchild;        }else {            p = s->arr[-- s->top];            p = p->rchild;        }    }     printf("\n");} void order_traverse(struct btree *t){    struct btree *p = t;    struct stack *s = (struct stack*)malloc(sizeof(struct stack) * 1);    s->top = 0;     while (s->top || p) {        if (p) {            s->arr[s->top ++] = p;            p = p->lchild;        }else {            p = s->arr[-- s->top];            printf("%d ", p->data);            p = p->rchild;        }    }     printf("\n");} void post_traverse(struct btree *t){    struct btree *p, *pre;    struct stack *s = (struct stack*)malloc(sizeof(struct stack) * 1);    s->top = 0;    pre = NULL;    p = t;     while (p || s->top) {        if (p) {            s->arr[s->top ++] = p;            p = p->lchild;        }else {            p = s->arr[-- s->top];            if (p->rchild == NULL || p->rchild == pre) {                printf("%d ", p->data);                pre = p;                p = NULL;            }else {                s->arr[s->top ++] = p;                p = p->rchild;            }        }    }     printf("\n");} void clean_tree(struct btree *t){    if (t) {        clean_tree(t->lchild);        clean_tree(t->rchild);        free(t);    }}/**************************************************************    Problem: 1201    User: wangzhengyi    Language: C    Result: Accepted    Time:70 ms    Memory:3284 kb****************************************************************/

后记

算法导论上二叉排序树应该是最简单最容易理解的，这里记录一下，当数据结构复习吧