Question 1 – Special (find the unique different element)

Question 1 – Special (find the unique different element)

Problem guarantees

  • Array length is odd and ≥ 3
  • All values equal except one
  • Input always valid

➡ Therefore no penalties for null, length checks, or empty handling.

C10 – Answer not assessable / no real attempt

(unchanged in spirit)

Use only when:

  • Empty or unrelated code
  • Logic impossible to infer

C1 – Core algorithm fails to isolate the unique element

Clearer name: Incorrect unique-element detection logic

Includes:

  • Returning last seen value without proof
  • Returning the common value
  • Logic that fails on normal valid inputs

Avoid overlap with C2, C3, C4

C2 – Incorrect identification of the common value baseline

Clearer name: Wrong baseline (common value) selection

Includes:

  • Wrong logic when using first 3 elements
  • Assigning wrong value as the majority element

C3 – Index and boundary logic errors

Clearer name: Invalid index usage within valid input size

Includes:

  • Accessing i+1 / i-1 incorrectly
  • Loop bounds that skip needed comparisons

C4 – Faulty counting approach

Clearer name: Incorrect frequency-based logic

Includes:

  • Miscounting
  • Wrong final comparison of counters

C5 – Correct detection but wrong returned value

Clearer name: Wrong return after correct detection

Includes:

  • Returning common value
  • Returning wrong variable

C6 – Method signature mismatch

(unchanged)

C7 – Broken control flow

Clearer name: Loop/return structure prevents correct traversal

Includes:

  • Premature break
  • Missing return

C8 – Variable misuse affecting correctness

(unchanged but tightened to core misuse only)

C9 – Minor syntax issues only

Explicitly small cap only

Question 2 – Uniques (remove consecutive duplicates)

Problem guarantees

  • Input array exists and is valid

➡ Do NOT penalize for null or empty handling

C10 – Not assessable

(unchanged)

C1 – Removing all duplicates instead of consecutive ones

Clearer name: Treating duplicates globally instead of consecutively

C2 – Wrong comparison logic between neighbors

(unchanged, but strictly about comparison correctness)

C3 – Incorrect result array sizing

Clearer name: Wrong output length calculation

C4 – Out-of-bounds index logic

(unchanged)

C5 – Unrelated or inefficient algorithm

Clearer name: Algorithm not matching required linear pass

C6 – Order not preserved

(unchanged)

C7 – Wrong or missing return

(unchanged)

C8 – Assumption of impossible edge cases

⚠ Only apply if violating valid inputs, not for missing null checks.

Example allowed failure:

  • Logic that breaks on array of length 1 (even though not required here)

C9 – Minor syntax only

(unchanged)

Question 3 – Interesting (min price ≥ 10)

Problem guarantees

  • No nulls in array
  • At least one product with price ≥ 10

➡ Do NOT penalize for null checks or for not handling “no valid product” cases

C10 – Not assessable

(unchanged)

C1 – Missing or wrong ≥10 filtering

(unchanged)

C2 – Wrong minimum selection logic

(unchanged)

C3 – Comparing objects instead of prices

(unchanged)

C4 – Loop/index structure breaks correctness

(unchanged)

C5 – Wrong return type or value

(unchanged)

C6 – Wrong minimum initialization

Clarified: only when it breaks valid guaranteed input

C7 – Wrong parameter/data structure

(unchanged)

C8 – Getter/setter misuse only

(unchanged)

C9 – Minor syntax only

(unchanged)