initial upload

2024/03/index.js

@@ -0,0 +1,28 @@
+import fs from 'node:fs'
+fs.readFile('input.txt', ({ encoding: "utf-8" }), (err, data) => {
+    const mul_regex = /mul\((\d+),(\d+)\)/g
+    const instruct_regex = /do(n't)?\(\)/g
+    let do_instruction = true
+    let result = 0
+    let multiplications_done = 0
+    const instructions = [...data.matchAll(instruct_regex)]
+    const matches = [...data.matchAll(mul_regex)]
+    for (let i = 0; i < instructions.length; i++) {
+        const now = instructions[i]
+        const then = (i + 1) in [...instructions.keys()] ? instructions[i + 1].index : data.length
+        do_instruction = now[0] === "do()" ? true : false
+        if (!do_instruction) { continue }
+        matches.forEach(match => {
+            if ((match.index > now.index && match.index < then && do_instruction) || (match.index < now.index && i == 0)) {
+                let [full, x, y] = match
+                result += parseInt(x) * parseInt(y) //mul(x, y)
+                multiplications_done += 1
+            }
+        })
+    }
+    console.log(`total multiplications:   ${matches.length}`)
+    console.log(`multiplications done:    ${multiplications_done}`)
+    console.log(`multiplications ignored: ${matches.length - multiplications_done}`)
+    console.log(`result:                  ${result}`)
+
+})