"Sword refers to offer" symmetric binary tree, "Sword refers to offer"

"Sword refers to offer" symmetric binary tree, "Sword refers to offer"

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Question link: http://www.nowcoder.com/practice/ff05d44dfdb04e1d83bdbdab320efbcb? Rp = 3 & ru =/ta/coding-interviews & qru =/ta/coding-interviews/question-ranking

Description
Implement a function to determine whether a binary tree is symmetric. Note: If a binary tree is the same as the image of this binary tree, it is defined as symmetric.

Ideas
Judge the symmetry of its Subtrees recursively from the root node

/*struct TreeNode {    int val;    struct TreeNode *left;    struct TreeNode *right;    TreeNode(int x) :            val(x), left(NULL), right(NULL) {    }};*/class Solution{public:bool isSymmetrical(TreeNode* pRoot){return check(pRoot,pRoot);}bool check(TreeNode *pLeft,TreeNode *pRight){if(pLeft==nullptr && pRight==nullptr)return true;if(pLeft==nullptr || pRight==nullptr)return false;if(pLeft->val != pRight->val)return false;return check(pLeft->left,pRight->right)&&check(pLeft->right,pRight->left);}};

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