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Abhishek Chaudhary
Abhishek Chaudhary

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Reach a Number

You are standing at position 0 on an infinite number line. There is a destination at position target.

You can make some number of moves numMoves so that:

  • On each move, you can either go left or right.
  • During the ith move (starting from i == 1 to i == numMoves), you take i steps in the chosen direction.

Given the integer target, return the minimum number of moves required (i.e., the minimum numMoves) to reach the destination.

Example 1:

Input: target = 2
Output: 3
Explanation:
On the 1st move, we step from 0 to 1 (1 step).
On the 2nd move, we step from 1 to -1 (2 steps).
On the 3rd move, we step from -1 to 2 (3 steps).

Example 2:

Input: target = 3
Output: 2
Explanation:
On the 1st move, we step from 0 to 1 (1 step).
On the 2nd move, we step from 1 to 3 (2 steps).

Constraints:

  • -109 <= target <= 109
  • target != 0

SOLUTION:

class Solution:
    def reachNumber(self, target: int) -> int:
        target = abs(target)
        total = 0
        steps = 0
        while total < target or (total - target) % 2 != 0:
            steps += 1
            total += steps
        return steps
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