Given a linked list, return the node where the cycle begins. If there is no cycle, return null.
Try solving it using constant additional space.
______ | | \/ | 1 -> 2 -> 3 -> 4
Return the node corresponding to node 3.
NOTE: You only need to implement the given function. Do not read input, instead use the arguments to the function. Do not print the output, instead return values as specified. Still have a question? Checkout Sample Codes for more details.