From 8e24234f5393eb84515207fa1e8ca0dfe86aea9c Mon Sep 17 00:00:00 2001
From: Christopher Bohn <bohn@unl.edu>
Date: Sun, 12 Dec 2021 17:16:02 -0600
Subject: [PATCH] Day 5 complete
---
2021/README.md | 16 ++-
2021/src/main/java/edu/unl/cse/bohn/Main.java | 4 +-
.../main/java/edu/unl/cse/bohn/Puzzle.java | 7 +-
.../java/edu/unl/cse/bohn/year2021/Day1.java | 5 +-
.../java/edu/unl/cse/bohn/year2021/Day2.java | 5 +-
.../java/edu/unl/cse/bohn/year2021/Day3.java | 5 +-
.../java/edu/unl/cse/bohn/year2021/Day4.java | 5 +-
.../java/edu/unl/cse/bohn/year2021/Day5.java | 108 ++++++++++++++++++
8 files changed, 138 insertions(+), 17 deletions(-)
create mode 100644 2021/src/main/java/edu/unl/cse/bohn/year2021/Day5.java
diff --git a/2021/README.md b/2021/README.md
index 9f4b90a..7290326 100644
--- a/2021/README.md
+++ b/2021/README.md
@@ -21,4 +21,18 @@ masks are cool.
This problem is a little more interesting since there are two stringly types in
the data, and one of them (the Bingo cards) requires a delimiter between
instances. Defining a custom class to represent Bingo cards simplifies the
-post-parsing problem.
\ No newline at end of file
+post-parsing problem.
+
+## Day 5
+
+This is a pretty straight-forward problem. The only real challenge is that there
+are two significant sub-problems: computing the line segments and computing the
+vent map. I suppose an alternative approach would be to compute the y=mx+b form
+of the lines and algebraically determining their intersections.
+
+I definitely need to get into the habit of thinking about computationally
+less-complex approaches. The straight-forward design I came up with for Day 5 is
+O(num_lines * num_rows * num_columns); the algebraic approach would be
+O(num_lines^2), so not too much of a big deal on this problem. But (I'm sure)
+there will be some problems whose straight-forward solution are a tad
+intractable.
\ No newline at end of file
diff --git a/2021/src/main/java/edu/unl/cse/bohn/Main.java b/2021/src/main/java/edu/unl/cse/bohn/Main.java
index f2d082f..c1a7573 100644
--- a/2021/src/main/java/edu/unl/cse/bohn/Main.java
+++ b/2021/src/main/java/edu/unl/cse/bohn/Main.java
@@ -21,13 +21,13 @@ public class Main {
Integer.toString(calendar.get(Calendar.YEAR)), scanner));
int day = Integer.parseInt(getUserInput("Enter puzzle day",
Integer.toString(calendar.get(Calendar.DAY_OF_MONTH)), scanner));
+ boolean useProductionData = getUserInput("Use sample data (Y/N)?", "Y", scanner).toUpperCase().charAt(0) != 'Y';
scanner.close();
ImportData dataSource = new ImportData(apiKey, year, day);
String className = Main.class.getPackageName() + ".year" + year + ".Day" + day;
Puzzle puzzle = null;
try {
- puzzle = (Puzzle)Class.forName(className).getConstructors()[0]
- .newInstance();
+ puzzle = (Puzzle)Class.forName(className).getConstructors()[0].newInstance(useProductionData);
} catch (ClassNotFoundException classNotFoundException) {
System.err.println("Could not find class " + className);
System.exit(1);
diff --git a/2021/src/main/java/edu/unl/cse/bohn/Puzzle.java b/2021/src/main/java/edu/unl/cse/bohn/Puzzle.java
index ef977db..b8e5910 100644
--- a/2021/src/main/java/edu/unl/cse/bohn/Puzzle.java
+++ b/2021/src/main/java/edu/unl/cse/bohn/Puzzle.java
@@ -4,9 +4,12 @@ import java.io.IOException;
import java.util.List;
public abstract class Puzzle {
- protected Integer day = null;
protected String sampleData = "";
- protected boolean isProductionReady = false;
+ protected boolean isProductionReady;
+
+ public Puzzle(boolean isProductionReady) {
+ this.isProductionReady = isProductionReady;
+ }
public abstract int computePart1(List<String> data);
public abstract int computePart2(List<String> data);
diff --git a/2021/src/main/java/edu/unl/cse/bohn/year2021/Day1.java b/2021/src/main/java/edu/unl/cse/bohn/year2021/Day1.java
index a19ed99..e1b1be5 100644
--- a/2021/src/main/java/edu/unl/cse/bohn/year2021/Day1.java
+++ b/2021/src/main/java/edu/unl/cse/bohn/year2021/Day1.java
@@ -9,8 +9,8 @@ import java.util.List;
public class Day1 extends Puzzle {
private List<Integer> depths;
- public Day1() {
- day = 1;
+ public Day1(boolean isProductionReady) {
+ super(isProductionReady);
sampleData = """
199
200
@@ -22,7 +22,6 @@ public class Day1 extends Puzzle {
269
260
263""";
- isProductionReady = true;
}
private int countIncreases(List<Integer> values) {
diff --git a/2021/src/main/java/edu/unl/cse/bohn/year2021/Day2.java b/2021/src/main/java/edu/unl/cse/bohn/year2021/Day2.java
index 43ef3f3..92585ee 100644
--- a/2021/src/main/java/edu/unl/cse/bohn/year2021/Day2.java
+++ b/2021/src/main/java/edu/unl/cse/bohn/year2021/Day2.java
@@ -16,8 +16,8 @@ public class Day2 extends Puzzle {
@SuppressWarnings("FieldCanBeLocal")
private int aim;
- public Day2() {
- day = 2;
+ public Day2(boolean isProductionReady) {
+ super(isProductionReady);
sampleData = """
forward 5
down 5
@@ -25,7 +25,6 @@ public class Day2 extends Puzzle {
up 3
down 8
forward 2""";
- isProductionReady = true;
}
@Override
diff --git a/2021/src/main/java/edu/unl/cse/bohn/year2021/Day3.java b/2021/src/main/java/edu/unl/cse/bohn/year2021/Day3.java
index 292ead5..fa94aab 100644
--- a/2021/src/main/java/edu/unl/cse/bohn/year2021/Day3.java
+++ b/2021/src/main/java/edu/unl/cse/bohn/year2021/Day3.java
@@ -12,8 +12,8 @@ public class Day3 extends Puzzle {
private int reportLength;
private int[] ones, zeroes;
- public Day3() {
- day = 3;
+ public Day3(boolean isProductionReady) {
+ super(isProductionReady);
sampleData = """
00100
11110
@@ -27,7 +27,6 @@ public class Day3 extends Puzzle {
11001
00010
01010""";
- isProductionReady = true;
}
@Override
diff --git a/2021/src/main/java/edu/unl/cse/bohn/year2021/Day4.java b/2021/src/main/java/edu/unl/cse/bohn/year2021/Day4.java
index 27b1ee3..46fa1c2 100644
--- a/2021/src/main/java/edu/unl/cse/bohn/year2021/Day4.java
+++ b/2021/src/main/java/edu/unl/cse/bohn/year2021/Day4.java
@@ -13,8 +13,8 @@ public class Day4 extends Puzzle {
private List<Integer> numbers;
private List<BingoCard> cards;
- public Day4() {
- day = 4;
+ public Day4(boolean isProductionReady) {
+ super(isProductionReady);
sampleData = """
7,4,9,5,11,17,23,2,0,14,21,24,10,16,13,6,15,25,12,22,18,20,8,19,3,26,1
@@ -35,7 +35,6 @@ public class Day4 extends Puzzle {
18 8 23 26 20
22 11 13 6 5
2 0 12 3 7""";
- isProductionReady = true;
}
private void parseData(List<String> data) {
diff --git a/2021/src/main/java/edu/unl/cse/bohn/year2021/Day5.java b/2021/src/main/java/edu/unl/cse/bohn/year2021/Day5.java
new file mode 100644
index 0000000..21a443d
--- /dev/null
+++ b/2021/src/main/java/edu/unl/cse/bohn/year2021/Day5.java
@@ -0,0 +1,108 @@
+package edu.unl.cse.bohn.year2021;
+
+import edu.unl.cse.bohn.Puzzle;
+
+import java.util.Arrays;
+import java.util.LinkedList;
+import java.util.List;
+
+@SuppressWarnings("unused")
+public class Day5 extends Puzzle {
+ public record Point(int x, int y) {
+ }
+
+ List<List<Point>> lineSegments;
+ int greatestX, greatestY;
+
+ public Day5(boolean isProductionReady) {
+ super(isProductionReady);
+ sampleData = """
+ 0,9 -> 5,9
+ 8,0 -> 0,8
+ 9,4 -> 3,4
+ 2,2 -> 2,1
+ 7,0 -> 7,4
+ 6,4 -> 2,0
+ 0,9 -> 2,9
+ 3,4 -> 1,4
+ 0,0 -> 8,8
+ 5,5 -> 8,2""";
+ }
+
+ private void parseData(List<String> data, boolean considerDiagonals) {
+ greatestX = greatestY = 0;
+ lineSegments = new LinkedList<>();
+ for (String datum : data) {
+ List<Point> lineSegment = new LinkedList<>();
+ String[] endPoints = datum.split(" -> ");
+ String[] point = endPoints[0].split(",");
+ int x1 = Integer.parseInt(point[0]);
+ int y1 = Integer.parseInt(point[1]);
+ point = endPoints[1].split(",");
+ int x2 = Integer.parseInt(point[0]);
+ int y2 = Integer.parseInt(point[1]);
+ greatestX = Integer.max(greatestX, Integer.max(x1, x2));
+ greatestY = Integer.max(greatestY, Integer.max(y1, y2));
+ if (x1 == x2) { // vertical line
+ int yMin = Integer.min(y1, y2);
+ int yMax = Integer.max(y1, y2);
+ for (int y = yMin; y <= yMax; y++) {
+ lineSegment.add(new Point(x1, y));
+ }
+ } else if (y1 == y2) { // horizontal line
+ int xMin = Integer.min(x1, x2);
+ int xMax = Integer.max(x1, x2);
+ for (int x = xMin; x <= xMax; x++) {
+ lineSegment.add(new Point(x, y1));
+ }
+ } else if (considerDiagonals) {
+ int y = y1;
+ if (x1 < x2) {
+ for (int x = x1; x <= x2; x++) {
+ lineSegment.add(new Point(x,y));
+ y = y1 < y2 ? y+1 : y-1;
+ }
+ } else {
+ for (int x = x1; x >= x2; x--) {
+ lineSegment.add(new Point(x,y));
+ y = y1 < y2 ? y+1 : y-1;
+ }
+ }
+ }
+ lineSegments.add(lineSegment);
+ }
+ }
+
+ private int countIntersectingVentLines() {
+ int[][] ventMap = new int[greatestX + 1][greatestY + 1];
+ for (int[] row : ventMap) {
+ Arrays.fill(row, 0);
+ }
+ for (List<Point> lineSegment : lineSegments) {
+ for (Point point : lineSegment) {
+ ventMap[point.x()][point.y()]++;
+ }
+ }
+ int numberOfIntersections = 0;
+ for (int x = 0; x <= greatestX; x++) {
+ for (int y = 0; y <= greatestY; y++) {
+ if (ventMap[x][y] > 1) {
+ numberOfIntersections++;
+ }
+ }
+ }
+ return numberOfIntersections;
+ }
+
+ @Override
+ public int computePart1(List<String> data) {
+ parseData(data, false);
+ return countIntersectingVentLines();
+ }
+
+ @Override
+ public int computePart2(List<String> data) {
+ parseData(data, true);
+ return countIntersectingVentLines();
+ }
+}
--
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