Cycle Detection or Tree Traversal | Dataford Interview Questions

Write a function to detect a cycle in a linked list or perform a specific tree traversal.

Implement the linked-list cycle option. The list is represented by nodes, where nodes[i] is the index of the next node, or -1 for the end, and head is the starting index. Return True if traversal from head eventually revisits a node, otherwise return False. Use O(1) auxiliary space and do not modify the input.

Constraints

0 <= len(nodes) <= 5000
head is -1 when the list is empty, otherwise 0 <= head < len(nodes)
Each next index is -1 or an integer from 0 through len(nodes) - 1
Only nodes reachable from head affect the result
The input must not be modified
Use O(1) auxiliary space

Function Signature

def has_cycle(nodes, head):

Your question is Cycle Detection or Tree Traversal. Start with the requirements in the Question tab.

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Problem

Write a function to detect a cycle in a linked list or perform a specific tree traversal.

Constraints

0 <= len(nodes) <= 5000
head is -1 when the list is empty, otherwise 0 <= head < len(nodes)
Each next index is -1 or an integer from 0 through len(nodes) - 1
Only nodes reachable from head affect the result
The input must not be modified
Use O(1) auxiliary space

Function Signature

def has_cycle(nodes, head):

Your question is Cycle Detection or Tree Traversal. 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.