1 問題

判斷二叉樹是不是對稱（遞歸和非遞歸實現）

如下二叉樹，就是對稱的二叉樹

23 3 1 4 4 1

如下二叉樹，就是非對稱的二叉樹?

23 3 1 4 4 2

?

?

?

?

?

2 代碼實現

#include <iostream> #include <queue>using namespace std;#define true 1 #define false 0typedef struct Node {int value;struct Node* left;struct Node* right; } Node;int isSymmetricTree(Node *head); int isSymmetric(Node *left, Node *right); int isSymmetricTree1(Node *head);/**判斷是否是對稱二叉樹（遞歸實現）*/ int isSymmetricTree(Node *head) {if (head == NULL){return true;} return isSymmetric(head, head); }int isSymmetric(Node *left, Node *right) {if (left == NULL && right == NULL){return true;}if (left == NULL || right == NULL){return false;}if (left->value != right->value){return false;}return isSymmetric(left->left, right->right) && isSymmetric(left->right, right->left); } /**判斷是否是對稱二叉樹（非遞歸實現）*/ int isSymmetricTree1(Node *head) {if (head == NULL){return true;} std::queue<Node *> queue1;std::queue<Node *> queue2;queue1.push(head->left);queue2.push(head->right);while(!queue1.empty() || !queue2.empty()){Node *left = queue1.front();Node *right = queue2.front();if ((left != NULL) && (right == NULL)){return false;}if ((left == NULL) && (right != NULL)){return false;} //因為上面情況只包含left為NULL和right不為NULL以及left不為NULL和right為NULL，//還包含2種情況，left和right都為NULL,以及left和right都不為NULL,所以我們left->value和right->判斷相等的時候//一定要記得對left和right都不是NULL的前提下才能調用->,下次切記，看到指針->的時候需要判斷指針是否為NULL//left和right都為NULL的時候，我們直接對queue1和queue2進行pop()操作if (left && right && (left->value != right->value)){return false;}queue1.pop();queue2.pop();if (left != NULL){queue1.push(left->left);queue1.push(left->right);}if (right != NULL){queue2.push(right->right);queue2.push(right->left);}}return true; }int main() {/* 2* 3 3 * 1 4 4 1 * */Node head1, node1, node2, node3, node4, node5, node6;Node head2, node7, node8;head1.value = 2;node1.value = 3;node2.value = 3;node3.value = 1;node4.value = 4;node5.value = 4;node6.value = 1;head1.left = &node1;head1.right = &node2;node1.left = &node3;node1.right = &node4;node2.left = &node5;node2.right = &node6;node3.left = NULL;node3.right = NULL;node4.left = NULL;node4.right = NULL;node5.left = NULL;node5.right = NULL;node6.left = NULL;node6.right = NULL;if (isSymmetricTree(&head1)){std::cout << "tree is symmertric" << std::endl;}else{std::cout << "tree is not symmertric" << std::endl;}if (isSymmetricTree1(&head1)){std::cout << "tree is symmertric" << std::endl;}else{std::cout << "tree is not symmertric" << std::endl;}return 0; }

?

?

?

3 運行結果

tree is symmertric tree is symmertric

?

總結

以上是生活随笔為你收集整理的剑指offer之中判断二叉树是不是对称二叉树（递归和非递归实现）的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。