days 10-11

11/input.txt

@@ -0,0 +1,10 @@
+4525436417
+1851242553
+5421435521
+8431325447
+4517438332
+3521262111
+3331541734
+4351836641
+2753881442
+7717616863

11/main.js

@@ -0,0 +1,44 @@
+const fs = require("fs")
+
+const input = fs.readFileSync("input.txt", "utf-8", err => {
+    err && console.error(err)
+}).split("\n").filter(line => line).map(line => line.split("").map(digit => parseInt(digit)))
+
+let flashed, flashCount = 0
+for (let i = 0;; i++){
+    flashed = Array(input.length).fill().map(arr => Array(input.length).fill(false))
+    for (let x = 0; x < input.length; x++){
+        for (let y = 0; y < input[x].length; y++){
+            incAndFlash(x, y)
+        }
+    }
+    flashCount += flashed.flat().filter(flash => flash).length
+    if (i === 99){
+        console.log(flashCount)
+    }
+    const all = input.flat()
+    if (all.length === all.filter(num => num === 0).length){
+        console.log(i + 1)
+        break
+    }
+}
+
+function incAndFlash(x, y){
+    if (flashed[y][x])
+        return
+    input[y][x]++
+    if (input[y][x] > 9){
+        input[y][x] = 0
+        flashed[y][x] = true
+        
+        for (let ny = y - 1; ny <= y + 1; ny++){
+            for (let nx = x - 1; nx <= x + 1; nx++){
+                if (x === nx && y === ny)
+                    continue
+                if (ny < 0 || nx < 0 || ny > input.length - 1 || nx > input[0].length - 1)
+                    continue
+                incAndFlash(nx, ny)
+            }
+        }
+    }
+}