From 5e5d59b58c32c648b5a384c62c3824eff18205d1 Mon Sep 17 00:00:00 2001
From: Christopher Bohn <bohn@unl.edu>
Date: Mon, 5 Dec 2022 09:12:27 -0600
Subject: [PATCH] Completed Year 2022 Day 5
---
2022/README.md | 7 +++++
.../java/edu/unl/cse/bohn/year2022/Day5.java | 30 ++++++++++++++-----
2 files changed, 30 insertions(+), 7 deletions(-)
diff --git a/2022/README.md b/2022/README.md
index 2398981..214ea26 100644
--- a/2022/README.md
+++ b/2022/README.md
@@ -150,8 +150,15 @@ Why do I have the feeling that there'll be some version of
### Part 2
+The difference here is how we move multiple crates from one stack to another.
+
### Refactoring opportunity
+With the difference between the two problems occurring inside a nested loop, extracting the commonality into a helper
+method (more than I've already done) isn't going to work. Passing in a pointer function would do nicely, but doing the
+Java equivalent is a PITA for such a small payoff. I think I'll use a boolean to indicate which of two crate movement
+techniques should be used.
+
## Day 6
(coming soon)
diff --git a/2022/src/main/java/edu/unl/cse/bohn/year2022/Day5.java b/2022/src/main/java/edu/unl/cse/bohn/year2022/Day5.java
index dfa5b32..7fcadf1 100644
--- a/2022/src/main/java/edu/unl/cse/bohn/year2022/Day5.java
+++ b/2022/src/main/java/edu/unl/cse/bohn/year2022/Day5.java
@@ -27,7 +27,7 @@ public class Day5 extends Puzzle {
@Override
public long computePart1(List<String> data) {
List<Stack<Character>> stacks = createStacks(data);
- rearrangeCrates(stacks, data);
+ rearrangeCrates(stacks, data, true);
String topsOfStacks = getTopsOfStacks(stacks);
System.out.println("Crates at the top of the stacks: " + topsOfStacks);
return 0;
@@ -35,6 +35,10 @@ public class Day5 extends Puzzle {
@Override
public long computePart2(List<String> data) {
+ List<Stack<Character>> stacks = createStacks(data);
+ rearrangeCrates(stacks, data, false);
+ String topsOfStacks = getTopsOfStacks(stacks);
+ System.out.println("Crates at the top of the stacks: " + topsOfStacks);
return 0;
}
@@ -64,16 +68,28 @@ public class Day5 extends Puzzle {
return Collections.unmodifiableList(stacks);
}
- private void rearrangeCrates(List<Stack<Character>> stacks, List<String> data) {
+ private void rearrangeCrates(List<Stack<Character>> stacks, List<String> data, boolean moveOneCrateAtATime) {
+ Stack<Character> crane = new Stack<>();
for (String instruction : data) {
if (instruction.startsWith("move")) { // then it really is an instruction
String[] tokens = instruction.strip().split(" ");
int numberOfCratesToMove = Integer.parseInt(tokens[1]);
- for (int i = 0; i < numberOfCratesToMove; i++) {
- int source = Integer.parseInt(tokens[3]) - 1; // -1 because the original stacks were 1-indexed
- int destination = Integer.parseInt(tokens[5]) - 1;
- char crate = stacks.get(source).pop();
- stacks.get(destination).push(crate);
+ int source = Integer.parseInt(tokens[3]) - 1; // -1 because the original stacks were 1-indexed
+ int destination = Integer.parseInt(tokens[5]) - 1;
+ if (moveOneCrateAtATime) {
+ for (int i = 0; i < numberOfCratesToMove; i++) {
+ char crate = stacks.get(source).pop();
+ stacks.get(destination).push(crate);
+ }
+ } else {
+ for (int i = 0; i < numberOfCratesToMove; i++) {
+ char crate = stacks.get(source).pop();
+ crane.push(crate);
+ }
+ while (!crane.empty()) {
+ char crate = crane.pop();
+ stacks.get(destination).push(crate);
+ }
}
}
}
--
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