From 7d835cdadf7d9f71f4f2ff88c51b58e7a24488c0 Mon Sep 17 00:00:00 2001
From: Aelita4 <kontakt@mikorosa.pl>
Date: Fri, 9 Dec 2022 21:39:00 +0100
Subject: [PATCH] 09_2

---
 day09/index.js | 43 +++++++++++++++++++++++++++++--------------
 1 file changed, 29 insertions(+), 14 deletions(-)

diff --git a/day09/index.js b/day09/index.js
index 849b25f..5ab1999 100644
--- a/day09/index.js
+++ b/day09/index.js
@@ -8,9 +8,21 @@ function isTailAdjacentToHead(head, tail) {
     return true;
 }
 
-const head = { x: 0, y: 0}, tail = { x: 0, y: 0 };
+const initX = 11, initY = 5;
+const rope = [
+    { x: initX, y: initY },
+    { x: initX, y: initY },
+    { x: initX, y: initY },
+    { x: initX, y: initY },
+    { x: initX, y: initY },
+    { x: initX, y: initY },
+    { x: initX, y: initY },
+    { x: initX, y: initY },
+    { x: initX, y: initY },
+    { x: initX, y: initY }
+];
 
-const visited = new Map([[ `0:0`, true ]]);
+const visited = new Map();
 
 input.split('\n').forEach(line => {
     const operations = line.split(' ');
@@ -33,20 +45,23 @@ input.split('\n').forEach(line => {
     }
 
     for(let i = 0; i < parseInt(operations[1]); i++) {
-        const oldHead = {};
-        oldHead.x = head.x;
-        oldHead.y = head.y;
+        rope[0].x += x;
+        rope[0].y += y;
 
-        head.x += x;
-        head.y += y;
-
-        if(!isTailAdjacentToHead(head, tail)) {
-            tail.x = oldHead.x;
-            tail.y = oldHead.y;
-
-            visited.set(`${tail.x}:${tail.y}`, true);
+        for(let ropeIndex = 1; ropeIndex < rope.length; ropeIndex++) {
+            if(!isTailAdjacentToHead(rope[ropeIndex - 1], rope[ropeIndex])) {
+                if(rope[ropeIndex - 1].x !== rope[ropeIndex].x && rope[ropeIndex - 1].y !== rope[ropeIndex].y) {
+                    rope[ropeIndex].x += (rope[ropeIndex - 1].x - rope[ropeIndex].x) > 0 ? 1 : -1;
+                    rope[ropeIndex].y += (rope[ropeIndex - 1].y - rope[ropeIndex].y) > 0 ? 1 : -1;
+                } else if(rope[ropeIndex - 1].x === rope[ropeIndex].x) {
+                    rope[ropeIndex].y += (rope[ropeIndex - 1].y - rope[ropeIndex].y) > 0 ? 1 : -1;
+                } else if(rope[ropeIndex - 1].y === rope[ropeIndex].y) {
+                    rope[ropeIndex].x += (rope[ropeIndex - 1].x - rope[ropeIndex].x) > 0 ? 1 : -1;
+                }
+            }            
         }
-    }
+        visited.set(`${rope[rope.length - 1].x}:${rope[rope.length - 1].y}`, true);
+    }   
 });
 
 console.log(visited.size);
\ No newline at end of file