Introduction

In this blog post, we will explore how to solve the LeetCode problem "754" using AI. LeetCode is a popular platform for preparing for coding interviews, and with the help of AI tools like Chatmagic, we can generate solutions quickly and efficiently - helping you pass the interviews and get the job offer without having to study for months.

Problem Statement

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

Explanation

• Absolute Value: Since moving left or right is symmetrical, convert the target to its absolute value. This simplifies the logic.
  • Iterative Sum and Adjustment: Incrementally calculate the sum of steps (1 + 2 + 3 + ...) until the sum is greater than or equal to the absolute target.
  • Parity Check: If the difference between the sum and the absolute target is even, then we can simply invert one of the moves in the series of steps to reach the target. If the difference is odd, continue adding steps until the difference becomes even.

• Runtime Complexity: O(sqrt(target)), Storage Complexity: O(1)

Code

    def reach_target(target: int) -> int:
    """
    Calculates the minimum number of moves required to reach the target.

    Args:
        target: The target position.

    Returns:
        The minimum number of moves required.
    """

    target = abs(target)
    steps = 0
    moves = 0
    while steps < target:
        moves += 1
        steps += moves

    while (steps - target) % 2 != 0:
        moves += 1
        steps += moves

    return moves