228. Treasure Chest Combinations

Easy · Math

A chest requires a 3-digit code where all digits are different and their sum equals `target`. Return how many such codes exist (digits 0–9).

Examples

Example 1
Input: target=6
Output: 4
Explanation: 012,021,102,120,201,210 → some have repeats, count only unique combos

Constraints

• 1 ≤ target ≤ 27