Doubly Linked List
Nodes linked in both directions, trading extra memory for O(1) backward traversal.
- 1 Lesson
Dry-run engine
Insert After a Node
Every node carries two addresses, so splicing one in is a handful of pointer writes — no shifting, no traversal.
- Input · Insert
- 25 after node 20
- Output · List
- Press play to run it
How it works
Wire the new node first (fresh.prev, fresh.next), then its neighbours (node.next.prev, node.next), so no address is overwritten before it has been copied.
heap_nodes[5] · prev ⇄ next
- node0x3c40 (20)
- fresh0x6d30 (25)
- Pointer write—
- Writes0 / 4
Each node stores two addresses, prev and next. We already hold node = 20 (0x3c40) and allocate fresh = 25 at 0x6d30; both of its pointers start as null.
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Course Contents
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