Solution: Circular Array Loop
Explore how to detect circular loops in an array of non-zero integers using fast and slow pointer techniques. This lesson guides you through cycle detection logic, ensuring movement directions are consistent, and helps you understand optimized approaches to solve this problem efficiently with minimal space.
Statement
There is a circular list of non-zero integers called nums. Each number in the list tells you how many steps to move forward or backward from your current position:
If
nums[i]is positive, movenums[i]steps forward.If
nums[i]is negative, movenums[i]steps backward.
As the list is circular:
Moving forward from the last element takes you back to the first element.
Moving backward from the first element takes you to the last element.
A cycle in this list means:
You keep moving according to the numbers, and you end up repeating a sequence of indexes.
All numbers in the cycle have the same sign (either all positive or all negative).
The cycle length is greater than 1 (it involves at least two indexes).
Return true if such a cycle exists in the list or false otherwise.
Constraints:
-
nums.length