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public class ArrayCycleLength {
  
  public static int findCycleLength(int[] arr) {
    if (arr.length <= 1) {
      return 0;
    }

    for (int i = 0; i < arr.length; i++) {
      if (arr[i] == 0) continue;  // Skip visited elements

      int slow, fast;
      slow = fast = i;
      boolean ifForward = arr[i] > 0;

      // Step 1: Detect Cycle
      while (true) {
        slow = getNextPosition(arr, slow, ifForward);
        if (slow == -1) break;

        fast = getNextPosition(arr, fast, ifForward);
        if (fast == -1) break;

        fast = getNextPosition(arr, fast, ifForward);
        if (fast == -1) break;

        if (slow == fast) {  
          // Step 2: Find cycle length
          return calculateCycleLength(arr, slow);
        }
      }
    }
    return 0;  // No cycle found
  }

  // Step 2: Function to calculate the length of the cycle
  private static int calculateCycleLength(int[] arr, int start) {
    int count = 1;
    int current = getNextPosition(arr, start, arr[start] > 0);

    while (current != start) {
      count++;
      current = getNextPosition(arr, current, arr[start] > 0);
    }
    return count;
  }

  // Helper function to get next index
  private static int getNextPosition(int[] arr, int index, boolean ifForward) {
    boolean direction = arr[index] >= 0;
    if (direction != ifForward) {
      return -1;
    }

    int nextIndex = (index + arr[index]) % arr.length;
    if (nextIndex < 0) {
      nextIndex += arr.length;
    }

    if (nextIndex == index) {
      return -1;
    }

    return nextIndex;
  }

  public static void main(String[] args) {
    int[] arr = {2, -1, 1, 2, 2};
    System.out.println("Cycle Length: " + findCycleLength(arr));  // Output: 3

    int[] arr2 = {-1, -2, -3, -4, -5, 6};
    System.out.println("Cycle Length: " + findCycleLength(arr2));  // Output: 0 (No cycle)
  }
}