How to delete a loop in one linked list?

Question

I'm not sure how to find the start of a loop without using O (N) memory and flags

Answer 1

• Locate the node inside the loop (see the "Response to 1800" section for details). Let me call it node C
• Find the length of the loop by moving the pointer from C until it reaches again C. The length of the loop is the number of steps that were taken. Let me call this length L
• Create a pointer that L moves forward from the start point and the other points to the start. Now push them one step at a time until they are gathered. This will be the entry point to the loop.

Time O (N), O (1).

btw, why do you need this?

Answer 2

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Answer 3

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Answer 4

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a- > b- > c → ...

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Answer 5

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