Linked Structures

Traverse and Print

Walk from the head pointer to null, visiting each node exactly once without random indexing.

Algorithm

The replay labels nodes by value, such as node(20), and never exposes object identity or memory addresses. This Bash DSA implementation uses the same small chain as the rest of the DSA track.

cursor A cursor reference names the node currently being visited.
null stop Traversal ends when the cursor reaches the null marker.

Basic Implementation

basic.sh
Replay: real traced execution (multi-file project)
#!/usr/bin/env bash
set -euo pipefail

render() {
  local idx="$1"
  local out=""
  while [[ "$idx" != "-1" ]]; do
    if [[ -n "$out" ]]; then out+=" -> "; fi
    out+="${value[$idx]}"
    idx="${next[$idx]}"
  done
  printf '%s -> null\n' "$out"
}

declare -A value
declare -A next
value[1]=10; next[1]=2
value[2]=20; next[2]=3
value[3]=30; next[3]=-1
head=1
render "$head"

  1. head ← 10 -> 20 -> 30 -> null

    1#!/usr/bin/env bash2set -euo pipefail
    values this step10 -> 20 -> 30 -> nullhead

  2. output ← 10

    6local out=""7while [[ "$idx" != "-1" ]]; do8  if [[ -n "$out" ]]; then out+=" -> "; fi
    values this step10outputnode(10)cursor

  3. output ← 10 -> 20

    6local out=""7while [[ "$idx" != "-1" ]]; do8  if [[ -n "$out" ]]; then out+=" -> "; fi
    values this step10 -> 20outputnode(20)cursor

  4. output ← 10 -> 20 -> 30 -> null

    6local out=""7while [[ "$idx" != "-1" ]]; do8  if [[ -n "$out" ]]; then out+=" -> "; fi
    values this step10 -> 20 -> 30 -> nulloutputnode(30)cursor

  5. stdout ← 10 -> 20 -> 30 -> null

    11  done12  printf '%s -> null\n' "$out"13}
    values this step10 -> 20 -> 30 -> nullstdout10 -> 20 -> 30 -> nulloutput

Complexity

  • Time: O(n)
  • Space: O(1)

Implementation notes

  • Keep the explicit node and pointer/reference operations; array shortcuts hide the linked-list state this lesson is meant to replay.
  • The final output prints the chain in a deterministic a -> b -> null form for cross-language comparison.