Day 8

Day 08/Part 1/index.ts

@@ -0,0 +1,56 @@
+import fs from 'node:fs';
+
+type Vec2d = {x: number, y: number};
+
+
+
+export default function runner(input: string) {
+
+  let h: number = 0, w : number = 0
+
+  const mapOfMaps: Map<string, Vec2d[]> = new Map();
+  const listOfAntinodes : Map<string, Vec2d> = new Map()
+
+  fs.readFile(`./${input}`, 'utf8', (err, data) => {
+    if (err) throw err;
+    data.split('\n').forEach((line, lineNo) => {
+      if(h < lineNo) h = lineNo
+      for (let colNo = 0; colNo < line.length; colNo++) {
+        if(w<colNo) w = colNo
+        const char = line.at(colNo)??""
+        if (char === '.') continue;
+        if(!mapOfMaps.has(char)) mapOfMaps.set(char, [])
+        mapOfMaps.get(char)?.push({x: colNo, y: lineNo})
+      }
+    })
+    mapOfMaps.forEach((value) => {
+      for (let i = 0; i < value.length; i++) {
+        for (let j = i+1; j < value.length; j++) {
+          // @ts-ignore
+          const locDiff: Vec2d = {x: value[i].x - value[j].x, y: value[i].y - value[j].y}
+          const negLocDiff: Vec2d = negate(locDiff)
+
+          // @ts-ignore
+          const posAntiNode: Vec2d = {x: value[i].x + locDiff.x, y: value[i].y + locDiff.y}
+          // @ts-ignore
+          const negAntiNode: Vec2d = {x: value[j].x + negLocDiff.x, y: value[j].y + negLocDiff.y}
+
+          addNode(posAntiNode, listOfAntinodes, h, w)
+          addNode(negAntiNode, listOfAntinodes, h, w)
+        }
+      }
+    })
+
+    console.log('Found ' + listOfAntinodes.size + ' antinodes')
+  })
+}
+
+function negate(input : Vec2d){
+  return {x: input.x*-1, y: input.y*-1}
+}
+
+function addNode(node: Vec2d, list: Map<string, Vec2d>, h: number, w: number){
+  if(node.x <0 || node.x>w || node.y<0 || node.y>h) return false;
+  if(!list.has(JSON.stringify(node))) list.set(JSON.stringify(node), node)
+  return true
+}

Day 08/Part 2/index.ts

@@ -0,0 +1,65 @@
+import fs from 'node:fs';
+
+type Vec2d = {x: number, y: number};
+
+
+
+export default function runner(input: string) {
+
+  let h: number = 0, w : number = 0
+
+  const mapOfMaps: Map<string, Vec2d[]> = new Map();
+  const listOfAntinodes : Map<string, Vec2d> = new Map()
+
+  fs.readFile(`./${input}`, 'utf8', (err, data) => {
+    if (err) throw err;
+    data.split('\n').forEach((line, lineNo) => {
+      if(h < lineNo) h = lineNo
+      for (let colNo = 0; colNo < line.length; colNo++) {
+        if(w<colNo) w = colNo
+        const char = line.at(colNo)??""
+        if (char === '.') continue;
+        if(!mapOfMaps.has(char)) mapOfMaps.set(char, [])
+        mapOfMaps.get(char)?.push({x: colNo, y: lineNo})
+      }
+    })
+    mapOfMaps.forEach((value) => {
+      for (let i = 0; i < value.length; i++) {
+        for (let j = i+1; j < value.length; j++) {
+          // @ts-ignore
+          calcEcho(value[i], value[j], listOfAntinodes, h, w)
+        }
+      }
+    })
+
+    console.log('Found ' + listOfAntinodes.size + ' antinodes')
+  })
+}
+
+function negate(input : Vec2d){
+  return {x: input.x*-1, y: input.y*-1}
+}
+
+function addNode(node: Vec2d, list: Map<string, Vec2d>, h: number, w: number){
+  if(node.x <0 || node.x>w || node.y<0 || node.y>h) return false;
+  if(!list.has(JSON.stringify(node))) list.set(JSON.stringify(node), node)
+  return true
+}
+
+function calcEcho(node1: Vec2d, node2: Vec2d, list: Map<string, Vec2d>, h: number, w: number){
+  const locDiff: Vec2d = {x: node1.x - node2.x, y: node1.y - node2.y}
+  const negLocDiff: Vec2d = negate(locDiff)
+
+  calcEchoRecurse(node1, locDiff, list, h, w)
+  calcEchoRecurse(node2, locDiff, list, h, w)
+  calcEchoRecurse(node1, negLocDiff, list, h, w)
+  calcEchoRecurse(node2, negLocDiff, list, h, w)
+}
+
+function calcEchoRecurse(node: Vec2d, vector: Vec2d, list: Map<string, Vec2d>, h: number, w: number){
+  const loc: Vec2d = {x: node.x + vector.x, y: node.y + vector.y}
+  if(addNode(loc, list, h, w))  {
+    calcEchoRecurse(loc,vector, list, h, w)
+  }
+}
+