X of a Kind in a Deck of Cards

EasyMathmath

Solve this the way you would in the interview: out loud, on a timer, with an AI interviewer asking follow-ups while you code. You get a scored report at the end.

Practice this as a mock interviewFree to start, no account needed

Problem

You are given an integer array deck where deck[i] is the number written on card i. Decide whether the whole deck can be split into one or more groups such that every group has the **same size X**, with X >= 2, and all cards within a group show the **same number**. Every card must belong to exactly one group. Return true if such a partition exists, otherwise false.

Examples

Input: deck = [1,2,3,4,4,3,2,1]
Output: true
Groups [1,1], [2,2], [3,3], [4,4] all have size 2.
Input: deck = [1,1,1,2,2,2,3,3]
Output: false
Counts are 3, 3, 2 — no common group size of at least 2 divides all of them.
Input: deck = [1,1,2,2,2,2]
Output: true
Use size 2: [1,1], [2,2], [2,2].

Constraints

  • 1 <= deck.length <= 10^4
  • 0 <= deck[i] < 10^4

What the interviewer grades

A correct solution is one of five scores. The report also grades problem understanding (did you clarify inputs and edge cases before coding), problem solving, communication while you work, code quality, and testing. See a sample report, or read up on the pattern in the lessons.

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