DSA · Theory

Two dimensional Binary Indexed Tree or Fenwick Tree

Theory

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Two dimensional Binary Indexed Tree or Fenwick Tree

Two dimensional Binary Indexed Tree or Fenwick Tree is a DSA topic. In plain words you use it for folder on disk in a file explorer. Don’t start with a slogan — start with that picture.

Smallest example: left < root < right. Type it, run it, and say what you see. If you can do that from memory, you know Two dimensional Binary Indexed Tree or Fenwick Tree.

From the example next to this theory — Two dimensional Binary Indexed Tree or Fenwick Tree: dry-run [4, 1, 3].

Trap — unbalanced BST becoming a list. Fix that before you talk about advanced DSA.

Viva — what is Two dimensional Binary Indexed Tree or Fenwick Tree? Then show left < root < right. Then name the trap.

Exam tip

What is Two dimensional Binary Indexed Tree or Fenwick Tree? Show this: left < root < right. Trap: unbalanced BST becoming a list.

Example

# Two dimensional Binary Indexed Tree or Fenwick Tree
data = [4, 1, 3]
print("start", data)
if data[0] > data[1]:
    data[0], data[1] = data[1], data[0]
print("after one step", data)

Two dimensional Binary Indexed Tree or Fenwick Tree: dry-run [4, 1, 3]. Say the list after one step.

Short notes

DefTwo dimensional Binary Indexed Tree or Fenwick Tree — folder on disk in a file explorer.
Ruleleft < root < right
Trapunbalanced BST becoming a list
Usea file explorer

DSA · Theory

Two dimensional Binary Indexed Tree or Fenwick Tree

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Theory

374/810

Two dimensional Binary Indexed Tree or Fenwick Tree

Two dimensional Binary Indexed Tree or Fenwick Tree is a DSA topic. In plain words you use it for folder on disk in a file explorer. Don’t start with a slogan — start with that picture.

Smallest example: left < root < right. Type it, run it, and say what you see. If you can do that from memory, you know Two dimensional Binary Indexed Tree or Fenwick Tree.

From the example next to this theory — Two dimensional Binary Indexed Tree or Fenwick Tree: dry-run [4, 1, 3].

Trap — unbalanced BST becoming a list. Fix that before you talk about advanced DSA.

Viva — what is Two dimensional Binary Indexed Tree or Fenwick Tree? Then show left < root < right. Then name the trap.

Exam tip

What is Two dimensional Binary Indexed Tree or Fenwick Tree? Show this: left < root < right. Trap: unbalanced BST becoming a list.

Example

# Two dimensional Binary Indexed Tree or Fenwick Tree
data = [4, 1, 3]
print("start", data)
if data[0] > data[1]:
    data[0], data[1] = data[1], data[0]
print("after one step", data)

Two dimensional Binary Indexed Tree or Fenwick Tree: dry-run [4, 1, 3]. Say the list after one step.

Short notes

DefTwo dimensional Binary Indexed Tree or Fenwick Tree — folder on disk in a file explorer.
Ruleleft < root < right
Trapunbalanced BST becoming a list
Usea file explorer

Two dimensional Binary Indexed Tree or Fenwick Tree

Example

Short notes

Questions

Two dimensional Binary Indexed Tree or Fenwick Tree

Example

Short notes

Questions