代码随想录day14

226.翻转二叉树

    void reverseTree(TreeNode* node){
        if(node == nullptr) return;
        if(node->left) reverseTree(node->left);
        if(node->right) reverseTree(node->right);
        TreeNode* tmp = node->left;
        node->left = node->right;
        node->right = tmp;
        
    }
    TreeNode* invertTree(TreeNode* root) {
        reverseTree(root);
        return root;
    }

101.对称二叉树

    bool compare(TreeNode* left, TreeNode* right){
        if(!left && !right){
            return true;
        }else if(!left && right){
            return false;
        }else if(left && !right){
            return false;
        }else if(left->val != right->val){
            return false;
        }
        bool com1 = compare(left->left, right->right);
        bool com2 = compare(left->right, right->left);
        bool result = com1 && com2;
        return result;
    }
    bool isSymmetric(TreeNode* root) {
        if(root == nullptr) return true;
        return compare(root->left, root->right);
    }

559.N叉树的最大深度

    int getDepth(Node* node){
        if(node == nullptr) return 0;
        int max = 0;
        for(std::vector<Node*>::iterator it = node->children.begin(); it != node->children.end(); ++it){
            int depth = getDepth(*it);
            if(depth > max){
                max = depth;
            }
        }
        int depth = 1 + max;
        return depth;
    }
    int maxDepth(Node* root) {
        return getDepth(root);
    }

111.二叉树的最小深度

    int digui(TreeNode* node){
        if(node == nullptr) return 0;
        int left = digui(node->left);
        int right = digui(node->right);
        if(!left){
            return 1 + right;
        }
        if(!right){
            return 1 + left;
        }
        int depth = 1 + min(left, right);
        return depth;
    }
    int minDepth(TreeNode* root) {
        return digui(root);
    }