二叉树反转

面试的毒瘤

#include<stdio.h>
#include<stdlib.h>
#include<string.h>

#define N 105

struct TreeNode
{
int val;
TreeNode* left;
TreeNode* right;
};

TreeNode *queue[N];
TreeNode *stack[N];

//创建树
void create_tree(TreeNode *&root)
{
char c;
scanf("%c", &c);
if (c == '0')
{
root = NULL;
}
else
{
root = (TreeNode*)malloc(sizeof(TreeNode));
root->val = c;
create_tree(root->left);
create_tree(root->right);
}
}

//打印树
void print_tree(TreeNode *root)
{
if (root != NULL)
{
printf("%c", root->val);
print_tree(root->left);
print_tree(root->right);
}
}

//采用递归
void reverse_tree(TreeNode *root)
{
if (root != NULL)
{
TreeNode *s;
s = root->left;
root->left = root->right;
root->right = s;
reverse_tree(root->left);
reverse_tree(root->right);
}
}

//采用队列
void reverse_tree_queue(TreeNode *root)
{
TreeNode *temp, *p = root;
int front, rear;
if (root != NULL)
{
queue[0] = root;
front = -1;
rear = 0;
while (front < rear)
{
p = queue[++front];
temp = p->left;
p->left = p->right;
p->right = temp;
if (p->left != NULL)
{
queue[++rear] = p->left;
}
if (p->right != NULL)
{
queue[++rear] = p->right;
}
}
}
}

//采用栈
void reverse_tree_stack(TreeNode *root)
{
int top = -1;
TreeNode *p, *bt = root;
if (root != NULL)
{
stack[++top] = root;
while (top != -1)
{
bt = stack[top--];
p = bt->right;
bt->right = bt->left;
bt->left = p;
if (bt->left)
{
stack[++top] = bt->left;
}
if (bt->right)
{
stack[++top] = bt->right;
}
}
}

}

int main(int argc, char* agrv[])
{
TreeNode *bt;
create_tree(bt);
print_tree(bt);
printf("\n");
reverse_tree(bt);
print_tree(bt);
printf("\n");
reverse_tree_queue(bt);
print_tree(bt);
printf("\n");
reverse_tree_stack(bt);
print_tree(bt);
printf("\n");

return 0;
}
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作者：sty945
来源：CSDN
原文：https://blog.csdn.net/sty945/article/details/82382452
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