v2 wip

Author: memark

2021/05/v2.ts

@@ -0,0 +1,146 @@
+const log = console.log;
+
+const useExample = 1;
+
+const filename = useExample ? "example.txt" : "input.txt";
+const data = Deno.readTextFileSync(filename);
+
+// "0,9 -> 5,9"
+// "8,0 -> 0,8"
+const vents = data.split("\n").map((l) =>
+  l.split(" -> ").map((r) => r.split(",")).map((xy) => ({
+    x: parseInt(xy[0]),
+    y: parseInt(xy[1]),
+  }))
+).map((v) => ({ start: v[0], stop: v[1] }));
+
+const ventsStraight = vents.filter(isStraightLine);
+
+type Coord = { x: number; y: number };
+type Vent = { start: Coord; stop: Coord };
+
+const ventsMaxX = Math.max(
+  ...vents.flat().map((v) => [v.start.x, v.stop.x]).flat(),
+);
+const ventsMaxY = Math.max(
+  ...vents.flat().map((v) => [v.start.y, v.stop.y]).flat(),
+);
+
+const size = Math.max(ventsMaxX, ventsMaxY) + 1;
+
+const scoresStraight = array0toN(size).map((y) =>
+  array0toN(size).map((x) => scorePoint(x, y, ventsStraight))
+);
+if (useExample) log(prettyFormat(scoresStraight));
+
+const totalScoreStraight = scoresStraight.flat().filter((s) => s >= 2).length;
+
+console.info(
+  "part1\t",
+  totalScoreStraight,
+); // 5, 6283
+
+const scores = array0toN(size).map((y) =>
+  array0toN(size).map((x) => scorePoint(x, y, vents))
+);
+if (useExample) log(prettyFormat(scores));
+
+const totalScore = scores.flat().filter((s) => s >= 2).length;
+
+console.info(
+  "part2\t",
+  totalScore,
+); //  12, 18864
+
+function scorePoint(
+  x: number,
+  y: number,
+  vents: Vent[],
+  shouldLog = false,
+): number {
+  return vents.filter((v) => pointIsOnVent(x, y, v, shouldLog)).length;
+}
+
+function pointIsOnVent(
+  x: number,
+  y: number,
+  v: Vent,
+  shouldLog = false,
+): boolean {
+  const x1 = v.start.x;
+  const x2 = v.stop.x;
+  const y1 = v.start.y;
+  const y2 = v.stop.y;
+
+  const lx = Math.abs(x1 - x2);
+  const ly = Math.abs(y1 - y2);
+
+  const minX = Math.min(v.start.x, v.stop.x);
+  const minY = Math.min(v.start.y, v.stop.y);
+  const maxX = Math.max(v.start.x, v.stop.x);
+  const maxY = Math.max(v.start.y, v.stop.y);
+
+  if (lx === 0) {
+    // vertical
+    return x === x1 && minY <= y && y <= maxY;
+  } else if (ly === 0) {
+    // horizontal
+    return y === y1 && minX <= x && x <= maxX;
+  } else {
+    // diagonal
+    if (lx !== ly) throw "Not 45 deg";
+
+    if (!(between(x1, x, x2) && between(y1, y, y2))) {
+      return false;
+    }
+
+    const dx = x - x1;
+    const dy = y - y1;
+
+    const rx = x2 > x1 ? 1 : -1;
+    const ry = y2 > y1 ? 1 : -1;
+
+    return (dx * rx === dy * ry);
+  }
+}
+
+function between(a: number, b: number, c: number): boolean {
+  return (a <= b && b <= c) || (a >= b && b >= c);
+}
+
+function isStraightLine(v: Vent): boolean {
+  return v.start.x == v.stop.x || v.start.y == v.stop.y;
+}
+
+import { red } from "https://deno.land/[email protected]/fmt/colors.ts";
+
+function prettyFormat(scores: number[][]) {
+  return scores.map((line) =>
+    line.map((p: number) =>
+      p == 0 ? "." : (p >= 2 ? red(p.toString()) : p.toString())
+    ).join("")
+  ).join("\n");
+}
+
+function array0toN(n: number) {
+  return [...Array(n).keys()];
+}
+
+// Från Johan Andersson
+//
+// (defun in-line? (p from to)
+//   (destructuring-bind ((px py) (fx fy) (tx ty)) (list p from to)
+//     (and (or (= fx tx)
+//              (= fy ty)
+//              (= (- fx fy) (- tx ty)))
+//          (<= (min fx tx) px (max fx tx))
+//          (<= (min fy ty) py (max fy ty)))))
+
+// DAY05> (in-line? '(2 3) '(2 3) '(3 4))
+// T
+// DAY05> (in-line? '(2 3) '(1 3) '(3 4))
+// NIL
+// DAY05> (in-line? '(3 0) '(2 0) '(4 0))
+// T
+// DAY05> (in-line? '(3 1) '(2 0) '(4 0))
+// NIL