15.2 done

2022/15/example.txt

@@ -0,0 +1,14 @@
+Sensor at x=2, y=18: closest beacon is at x=-2, y=15
+Sensor at x=9, y=16: closest beacon is at x=10, y=16
+Sensor at x=13, y=2: closest beacon is at x=15, y=3
+Sensor at x=12, y=14: closest beacon is at x=10, y=16
+Sensor at x=10, y=20: closest beacon is at x=10, y=16
+Sensor at x=14, y=17: closest beacon is at x=10, y=16
+Sensor at x=8, y=7: closest beacon is at x=2, y=10
+Sensor at x=2, y=0: closest beacon is at x=2, y=10
+Sensor at x=0, y=11: closest beacon is at x=2, y=10
+Sensor at x=20, y=14: closest beacon is at x=25, y=17
+Sensor at x=17, y=20: closest beacon is at x=21, y=22
+Sensor at x=16, y=7: closest beacon is at x=15, y=3
+Sensor at x=14, y=3: closest beacon is at x=15, y=3
+Sensor at x=20, y=1: closest beacon is at x=15, y=3

2022/15/index.js

@@ -0,0 +1,44 @@
+const fs = require('fs/promises');
+
+const sum = (arr) => arr.reduce((total, num) => total+num, 0);
+const arrayOfLength = n => Array.from(Array(n).keys()).map(() => {});
+
+const parseXY = str => str.match(/x=(.*), y=(.*)$/).slice(1).map(x => BigInt(x));
+
+const ROW = 2000000n;
+
+const abs = x => x < 0n ? x * -1n : x;
+const main = async () => {
+  const input = (await fs.readFile("./input.txt", 'utf8')).split("\n").slice(0, -1);
+  console.log(input);
+  const sets = input.map(row => row.split(": ").map(parseXY));
+  const map = new Set();
+
+
+  const getDistance = (x1, y1, x2, y2) => abs(x1 - x2) + abs(y1 - y2);
+
+  const fillRow = (centerX, radius) => {
+    console.log("Fill radius: ", radius);
+    for(let i = centerX - radius; i <= centerX + radius; ++i) {
+      map.add(i);
+    }
+  }
+
+  for(let [[x, y], b] of sets) {
+    const radius = getDistance(x, y, ...b);
+    const halfWidth = radius - abs(ROW - y)
+    if(halfWidth > 0) {
+      fillRow(x, halfWidth);
+    }
+  }
+
+  for(let [_, b] of sets) {
+    if(b[1] === ROW) {
+      map.delete(b[0]);
+    }
+  }
+
+  console.log("ANSWER: ", map.size);
+}
+
+main();

2022/15/index2.js

@@ -0,0 +1,64 @@
+// Comnbining all ranges (min to max) from each beacon at each level of Y may be fast enough
+const fs = require('fs/promises');
+
+const sum = (arr) => arr.reduce((total, num) => total+num, 0);
+const arrayOfLength = n => Array.from(Array(n).keys()).map(() => {});
+
+const parseXY = str => str.match(/x=(.*), y=(.*)$/).slice(1).map(x => parseInt(x));
+
+const HEIGHT = 4000000;
+
+const doTouch = (a, b, a2, b2) => {
+  const a1 = a - 1;
+  const b1 = b + 1;
+  if(b1 >= a2 && a1 <= b2) {
+    return true;
+  }
+  return false;
+}
+const getStartEnd = (x, rad) => [x-rad, x+rad];
+const getDistance = (x1, y1, x2, y2) => abs(x1 - x2) + abs(y1 - y2);
+
+const combineTouching = (a,b,c,d) => {
+  return [Math.min(a,c), Math.max(b,d)];
+}
+
+const abs = x => x < 0 ? x * -1 : x;
+const main = async () => {
+  const input = (await fs.readFile("./input.txt", 'utf8')).split("\n").slice(0, -1);
+  const sets = input.map(row => row.split(": ").map(parseXY));
+
+  const sensors = sets.map(([[sX, sY], [bX, bY]]) => {
+    return [sX, sY, getDistance(sX, sY, bX, bY)];
+  });
+
+  for(let row = 0; row <= HEIGHT; row++) {
+      const coveredArea = sensors.filter(
+        ([_, y, rad]) => Math.abs(row-y) <= rad
+      ).map(
+        ([x, y, rad]) => getStartEnd(x, rad - Math.abs(row - y))
+      ).sort(
+        (a, b) => a[0] - b[0]
+      ).reduce((ranges, [a1, b1]) => {
+        if(!ranges) {
+          return [[a1, b1]];
+        }
+        const [a, b] = ranges[ranges.length - 1];
+        if(doTouch(a, b, a1, b1)){
+          ranges[ranges.length - 1] = combineTouching(a, b, a1, b1);
+        } else {
+          ranges.push([a1, b1]);
+        }
+        return ranges;
+      }, false);
+      if(coveredArea.length > 1) {
+        console.log("FOUND IT! Answer: ", (coveredArea[0][1] + 1) * 4000000 + row);
+        process.exit();
+      }
+    if(row % 100000 === 0) {
+        console.log("DONE: ", row);
+      }
+    }
+}
+
+main();

2022/15/input.txt

@@ -0,0 +1,23 @@
+Sensor at x=3907621, y=2895218: closest beacon is at x=3790542, y=2949630
+Sensor at x=1701067, y=3075142: closest beacon is at x=2275951, y=3717327
+Sensor at x=3532369, y=884718: closest beacon is at x=2733699, y=2000000
+Sensor at x=2362427, y=41763: closest beacon is at x=2999439, y=-958188
+Sensor at x=398408, y=3688691: closest beacon is at x=2275951, y=3717327
+Sensor at x=1727615, y=1744968: closest beacon is at x=2733699, y=2000000
+Sensor at x=2778183, y=3611924: closest beacon is at x=2275951, y=3717327
+Sensor at x=2452818, y=2533012: closest beacon is at x=2733699, y=2000000
+Sensor at x=88162, y=2057063: closest beacon is at x=-109096, y=390805
+Sensor at x=2985370, y=2315046: closest beacon is at x=2733699, y=2000000
+Sensor at x=2758780, y=3000106: closest beacon is at x=3279264, y=2775610
+Sensor at x=3501114, y=3193710: closest beacon is at x=3790542, y=2949630
+Sensor at x=313171, y=1016326: closest beacon is at x=-109096, y=390805
+Sensor at x=3997998, y=3576392: closest beacon is at x=3691556, y=3980872
+Sensor at x=84142, y=102550: closest beacon is at x=-109096, y=390805
+Sensor at x=3768533, y=3985372: closest beacon is at x=3691556, y=3980872
+Sensor at x=2999744, y=3998031: closest beacon is at x=3691556, y=3980872
+Sensor at x=3380504, y=2720962: closest beacon is at x=3279264, y=2775610
+Sensor at x=3357940, y=3730208: closest beacon is at x=3691556, y=3980872
+Sensor at x=1242851, y=838744: closest beacon is at x=-109096, y=390805
+Sensor at x=3991401, y=2367688: closest beacon is at x=3790542, y=2949630
+Sensor at x=3292286, y=2624894: closest beacon is at x=3279264, y=2775610
+Sensor at x=2194423, y=3990859: closest beacon is at x=2275951, y=3717327