day 5 p1 & init p2

solutions/04-b.ts

@@ -32,7 +32,6 @@ class DayFour implements Solvable {
                     results.push(matrix[y][x] + matrix[y - 1][x + 1] + matrix[y - 2][x + 2] + matrix[y - 3][x + 3])
                 }
             }
-
             if (allowed.bottom) {
                 // bottom
                 results.push(matrix[y][x] + matrix[y + 1][x] + matrix[y + 2][x] + matrix[y + 3][x])
@@ -45,7 +44,6 @@ class DayFour implements Solvable {
                     results.push(matrix[y][x] + matrix[y + 1][x + 1] + matrix[y + 2][x + 2] + matrix[y + 3][x + 3])
                 }
             }
-
             if (allowed.left) {
                 // left        
                 results.push(matrix[y][x] + matrix[y][x - 1] + matrix[y][x - 2] + matrix[y][x - 3])

solutions/05.ts

@@ -0,0 +1,64 @@
+
+import { solvables } from "../main.ts";
+
+import type { Solvable } from "../solvable.ts";
+import { readInput } from "../utils.ts";
+
+class DayFive implements Solvable {
+    input: string[] = readInput('05').trim().split('\n\n')
+    rules: number[][] = this.input[0].split('\n').map((input: string) => input.split('|').map(rule => Number.parseInt(rule)))
+    updates: number[][] = this.input[1].split('\n').map(line => line.split(',').map(update => Number.parseInt(update)))
+
+    invalidUpdates: number[][] = []
+
+    followsRules = (update: number[]): [boolean, number, number] => {
+        for (const rule of this.rules) {
+            const left = update.findIndex((val) => val === rule[0])
+            const right = update.findIndex((val) => val === rule[1])
+            if (left === -1 || right === -1) continue
+            if (left > right) return [false, left, right]
+        }
+        return [true, -1, -1]
+    }
+
+    middles = (updates: number[][]): number =>
+        updates
+            .map((update: number[]) => update[Math.floor(update.length / 2)])
+            .reduce((prev, curr) => prev + curr)
+
+    public part1(): Solvable {
+        const validUpdates: number[][] = []
+        this.updates.forEach(update => {
+            if (this.followsRules(update)[0]) {
+                validUpdates.push(update)
+            } else {
+                this.invalidUpdates.push(update)
+            }
+        })
+        const result = this.middles(validUpdates)
+        console.log(result)
+
+        return this
+    }
+
+    public part2(): Solvable {
+        const invalidUpdates = this.invalidUpdates
+        const sort = (update: number[]): number[] => {
+            const [compliant, leftIdx, rightIdx] = this.followsRules(update)
+            if (!compliant) {
+                // remove offending item and just move it to the back
+                const removedLeft = update.splice(leftIdx, 1)
+                const rebuiltUpdate = [...update.slice(0, rightIdx), removedLeft[0], ...update.slice(rightIdx, -1)]
+                return sort(rebuiltUpdate)
+            } else {
+                return update
+            }
+        }
+        const fixedUpdates = invalidUpdates.map(updates => sort(updates))
+        const result = this.middles(fixedUpdates)
+        console.log(result)
+        return this
+    }
+}
+
+solvables.push(new DayFive())