From 59e650785cf4b4bf9bdec0d679e6c05b41fc29fb Mon Sep 17 00:00:00 2001
From: Mark Jeeninga <mark.jeeninga@control.lth.se>
Date: Sat, 14 Dec 2024 13:10:17 +0000
Subject: [PATCH] Day 6 Mark
---
day 6/day_6_mark.js | 64 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 64 insertions(+)
create mode 100644 day 6/day_6_mark.js
diff --git a/day 6/day_6_mark.js b/day 6/day_6_mark.js
new file mode 100644
index 0000000..b4b0589
--- /dev/null
+++ b/day 6/day_6_mark.js
@@ -0,0 +1,64 @@
+lines = input.split("\n").map(x=>x.split(""))
+n = lines.length
+m = lines[0].length
+range = x => [...Array(x).keys()]
+getEntry = x => lines[x[0]] ? lines[x[0]][x[1]] : undefined
+setEntry = (x,y) => x[0] >= 0 && x[0] < n && x[1] >= 0 && x[1] < m ? lines[x[0]][x[1]] = y : undefined
+done = true
+direction = 0
+directions = [[-1,0],[0,1],[1,0],[0,-1]];
+guardStart = undefined
+range(n).some(i => range(m).some(j => getEntry([i,j]) == "^" ? guardStart = [i,j] : false))
+guard = guardStart;
+print = () => lines.map(x => x.join("")).join("\n")
+while(guard){
+ nextGuard = [guard[0]+directions[direction][0], guard[1]+directions[direction][1]]
+ while(getEntry(nextGuard) == "#"){
+ direction = (direction + 1) % 4
+ nextGuard = [guard[0]+directions[direction][0], guard[1]+directions[direction][1]]
+ }
+ setEntry(guard,"X")
+ guard = setEntry(nextGuard, "^") ? nextGuard : undefined
+}
+
+output1 = range(n).reduce((x,i) => x+range(m).reduce((y,j) => y+(getEntry([i,j]) == "X" ? 1 : 0),0),0)
+
+isLoop = x => {
+ if(x.toString() == guardStart.toString())
+ return false;
+
+ lines = input.split("\n").map(x=>x.split(""))
+ setEntry(x, "#")
+ guard = guardStart;
+ getEntry = x => lines[x[0]] ? lines[x[0]][x[1]] : undefined
+ setEntry = (x,y) => x[0] >= 0 && x[0] < n && x[1] >= 0 && x[1] < m ? lines[x[0]][x[1]] = y : undefined
+ step = 0
+ direction = 0
+ while(guard){
+ entry = typeof(getEntry(guard)) != "number" ? 0 : getEntry(guard)
+ if(entry & 2**direction){
+ console.log(-1)
+ return true
+ }
+ setEntry(guard, entry | (2**direction))
+ nextGuard = [guard[0]+directions[direction][0], guard[1]+directions[direction][1]]
+ counter = 0
+ while(getEntry(nextGuard) == "#" && counter < 4){
+ direction = (direction + 1) % 4
+ nextGuard = [guard[0]+directions[direction][0], guard[1]+directions[direction][1]]
+ counter += 1
+ }
+ if(counter == 4){
+ console.log(-2)
+ return false;
+ }
+ if(step > m*n){
+ console.log(-3)
+ return false;
+ }
+ guard = getEntry(nextGuard) ? nextGuard : undefined
+ step += 1
+ }
+ return false;
+}
+output2 = range(n).reduce((x,i) => x+range(m).reduce((y,j) => y+isLoop([i,j]),0),0)
--
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