DSA · Theory

Two dimensional Binary Indexed Tree or Fenwick Tree

Theory

374/810

Two dimensional Binary Indexed Tree or Fenwick Tree

Two dimensional Binary Indexed Tree or Fenwick Tree is simple if you keep it on paper. Amit uses it for folder on disk in a file explorer.

Keep Two dimensional Binary Indexed Tree or Fenwick Tree small. Amit should finish folder on disk in a few lines, not a 40-line dump.

Two dimensional Binary Indexed Tree or Fenwick Tree exists so Amit can keep folder on disk correct in a file explorer.

Use Two dimensional Binary Indexed Tree or Fenwick Tree when folder on disk must stay clear. If a simpler DSA step works, use that instead.

Don’t do this with Two dimensional Binary Indexed Tree or Fenwick Tree: unbalanced BST becoming a list. Interviewers spot it in ten seconds.

After Two dimensional Binary Indexed Tree or Fenwick Tree, Amit should still remember unbalanced BST becoming a list.

Viva for Two dimensional Binary Indexed Tree or Fenwick Tree: what it is → left < root < right → the mistake (unbalanced BST becoming a list).

Exam tip

Board: folder on disk. Dry-run Two dimensional Binary Indexed Tree or Fenwick Tree. Name the 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 — Amit uses it for folder on disk in a file explorer.
RuleTwo dimensional Binary Indexed Tree or Fenwick Tree → left < root < right.
RememberTwo dimensional Binary Indexed Tree or Fenwick Tree + time vs memory (a file explorer).
UseTwo dimensional Binary Indexed Tree or Fenwick Tree in a file explorer (folder on disk).
TrapTwo dimensional Binary Indexed Tree or Fenwick Tree — unbalanced BST becoming a list.
ExTwo dimensional Binary Indexed Tree or Fenwick Tree → folder on disk.

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 simple if you keep it on paper. Amit uses it for folder on disk in a file explorer.

Keep Two dimensional Binary Indexed Tree or Fenwick Tree small. Amit should finish folder on disk in a few lines, not a 40-line dump.

Two dimensional Binary Indexed Tree or Fenwick Tree exists so Amit can keep folder on disk correct in a file explorer.

Use Two dimensional Binary Indexed Tree or Fenwick Tree when folder on disk must stay clear. If a simpler DSA step works, use that instead.

Don’t do this with Two dimensional Binary Indexed Tree or Fenwick Tree: unbalanced BST becoming a list. Interviewers spot it in ten seconds.

After Two dimensional Binary Indexed Tree or Fenwick Tree, Amit should still remember unbalanced BST becoming a list.

Viva for Two dimensional Binary Indexed Tree or Fenwick Tree: what it is → left < root < right → the mistake (unbalanced BST becoming a list).

Exam tip

Board: folder on disk. Dry-run Two dimensional Binary Indexed Tree or Fenwick Tree. Name the 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 — Amit uses it for folder on disk in a file explorer.
RuleTwo dimensional Binary Indexed Tree or Fenwick Tree → left < root < right.
RememberTwo dimensional Binary Indexed Tree or Fenwick Tree + time vs memory (a file explorer).
UseTwo dimensional Binary Indexed Tree or Fenwick Tree in a file explorer (folder on disk).
TrapTwo dimensional Binary Indexed Tree or Fenwick Tree — unbalanced BST becoming a list.
ExTwo dimensional Binary Indexed Tree or Fenwick Tree → folder on disk.

Two dimensional Binary Indexed Tree or Fenwick Tree

Example

Short notes

Questions

Two dimensional Binary Indexed Tree or Fenwick Tree

Example

Short notes

Questions