coding.md

Coding Notes

Leetcode

• Given a binary tree, find its maximum depth (the number of nodes along the longest path from the root node down to the farthest leaf node)

// depth-first search
int maxDepth(TreeNode *root)
{
    return root == NULL ? 0 : max(maxDepth(root -> left), maxDepth(root -> right)) + 1;
}

// breadth-first search
int maxDepth(TreeNode *root)
{
    if(root == NULL)
        return 0;

    int res = 0;
    queue<TreeNode *> q;
    q.push(root);
    while(!q.empty())
    {
        ++ res;
        for(int i = 0, n = q.size(); i < n; ++ i)
        {
            TreeNode *p = q.front();
            q.pop();

            if(p -> left != NULL)
                q.push(p -> left);
            if(p -> right != NULL)
                q.push(p -> right);
        }
    }

    return res;
}