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
 */
impl Solution {
  pub fn reach_a_number(target: i32) -> i32 {
    let target = target.unsigned_abs() as i64;
    let mut sum = 0i64;
    let mut n = 0i64;
    loop {
      n += 1;
      sum += n;
      if sum >= target && (sum - target) % 2 == 0 {
        return n as i32;
      }
    }
  }
}