Detect Linked List Loop | Dataford Interview Questions

How would you find if there is a loop in a linked list?

Represent the linked list with values and pos: node i points to node i + 1, except the final node points to node pos; pos = -1 means it points to None. Implement has_cycle(values, pos) and return True if the structure contains a cycle, otherwise return False. The function must use constant extra space and must not modify the input.

Constraints

0 <= len(values) <= 1000
-10^9 <= values[i] <= 10^9
pos is either -1 or an integer from 0 through len(values) - 1
The input representation describes a singly linked list

Function Signature

def has_cycle(values, pos):

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Problem

How would you find if there is a loop in a linked list?

Constraints

0 <= len(values) <= 1000
-10^9 <= values[i] <= 10^9
pos is either -1 or an integer from 0 through len(values) - 1
The input representation describes a singly linked list

Function Signature

def has_cycle(values, pos):

Your question is Detect Linked List Loop. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.