代码随想录算法训练营第十三天|110.平衡二叉树、257. 二叉树的所有路径-优快云博客

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代码随想录算法训练营第十三天

110.平衡二叉树

class Solution {
public:
    int getHeight(TreeNode* node) {
        if(node == nullptr) return 0;
        int leftHeight = getHeight(node->left);
        if(leftHeight == -1) return -1;
        int rightHeight = getHeight(node->right);
        if(rightHeight == -1) return -1;
        if(abs(leftHeight - rightHeight) > 1) return -1;
        return 1 + max(leftHeight, rightHeight);
    }
    bool isBalanced(TreeNode* root) {
        int height = getHeight(root);
        if(height >= 0) return true;
        else return false;
    }
};

257. 二叉树的所有路径

题目链接
 文章讲解
 视频讲解

心得

class Solution {
public:
    void traversal(TreeNode* node, vector<int>& path, vector<string>& result) {
        path.push_back(node->val);
        if(node->left == nullptr && node->right == nullptr) {
            string s;
            for(int i = 0; i < path.size() - 1; i++) {
                s += to_string(path[i]);
                s += "->";
            }
            s += to_string(path[path.size() - 1]);
            result.push_back(s);
            return;
        }
        if(node->left) {
            traversal(node->left, path, result);
            path.pop_back();
        }
        if(node->right) {
            traversal(node->right, path, result);
            path.pop_back();
        }
    }
    vector<string> binaryTreePaths(TreeNode* root) {
        vector<string> result;
        vector<int> path;
        traversal(root, path, result);
        return result;
    }
};