# How do you find the lowest common ancestor in Python?

## How do you find the lowest common ancestor in Python?

Lowest Common Ancestor of a Binary Tree in Python

1. If the tree is empty, then return null.
2. if p and q both are same as root, then return root.
3. left := LCA of left subtree of the root using p and q.
4. right := LCA of right subtree of the root using p and q.
5. if left and right both are non-zero, then return root.

How do you find the lowest common ancestor?

In ontologies, the lowest common ancestor is also known as the least common ancestor. In a tree data structure where each node points to its parent, the lowest common ancestor can be easily determined by finding the first intersection of the paths from v and w to the root.

What is LCA programming?

In Graph Theory and Computer Science, the Lowest Common Ancestor(LCA) of two nodes u and v in a tree or a directed acyclic graph(DAG) is the lowest node that has both u and v as descendants,where we define each node to be a descendant of itself .

### What is lowest common ancestor of 2 nodes?

The lowest common ancestor (LCA) of two nodes x and y in a binary tree is the lowest (i.e., deepest) node that has both x and y as descendants, where each node can be a descendant of itself (so if x is reachable from w , w is the LCA).

How do you find the lowest common ancestor LCA in a binary tree?

Lowest Common Ancestor in a Binary Tree | Set 1

1. Method 1 (By Storing root to n1 and root to n2 paths):
2. 1) Find a path from the root to n1 and store it in a vector or array.
3. 2) Find a path from the root to n2 and store it in another vector or array.
4. 3) Traverse both paths till the values in arrays are the same.

Is a node A descendant of itself?

Every node is an descendent of itself. A proper descendent of n is any node y for which n is an ancestor of y and y is not the same node as n.

#### What is meant by lowest common ancestor?

According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between two nodes p and q as the lowest node in T that has both p and q as descendants (where we allow a node to be a descendant of itself).”

Is the Binarysearch algorithm the same thing as a Binarysearchtree why not?

As often presented, binary search refers to the array based algorithm presented here, and binary search tree refers to a tree based data structure with certain properties. However, the properties that binary search requires and the properties that binary search trees have make these two sides of the same coin.