Reach a Number

MediumMathmath

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 stand at position 0 on an infinite number line and want to reach position target. On move i (starting from i = 1) you must step exactly i units, either left or right. Return the **minimum** number of moves needed to land exactly on target. Aim for a solution that does not simulate every left/right choice.

Examples

Input: target = 2
Output: 3
Move 1 right to 1, move 2 left to -1, move 3 right to 2.
Input: target = 3
Output: 2
Move 1 right to 1, move 2 right to 3.

Constraints

  • `-10^9 <= target <= 10^9`
  • `target != 0`

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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