Stage 1 · Code
Linked Lists
Reverse List
Iterative and recursive list reversal techniques.
6 min readMastering Data Structures & Algorithms for Software Engineering InterviewsCode
Iterative Reversal
Use three pointers: prev (reversed part), curr (current), next (save next). Iterate, reverse links, advance pointers.
Goiterative-reverse.go
12 linesLn 1, Col 1Go
prev starts nil (end of reversed). Each iteration: save next, point current to prev, move prev and curr forward. Returns new head.
Recursive Reversal
Recurse to end, then reverse links on unwind. Base case: empty or single node. Return new head from deepest call.
Gorecursive-reverse.go
16 linesLn 1, Col 1Go
Recursion goes to last node (new head). On unwind: head.Next is the node after current; point it back to current. Set current.Next = nil to break old link.
Partial Reverse (Reverse Between)
Reverse sublist from position left to right (1-indexed). Connect reversed portion back to unchanged prefix/suffix.
Goreverse-between-positions.go
23 linesLn 1, Col 1Go
Dummy head handles left=1. prev points to node before reversed portion. Iteratively pull next node to front of reversed portion (head insertion style).
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