From 320b035125555cbc3aeb116cfc6a69600a5ee845 Mon Sep 17 00:00:00 2001
From: John Shaver <john.shaver@emsibg.com>
Date: Thu, 15 Dec 2022 11:33:23 -0800
Subject: [PATCH] 15.2 done

---
 2022/15/index.js  |  2 --
 2022/15/index2.js | 64 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 64 insertions(+), 2 deletions(-)
 create mode 100644 2022/15/index2.js

diff --git a/2022/15/index.js b/2022/15/index.js
index 585c3f8..271eeba 100644
--- a/2022/15/index.js
+++ b/2022/15/index.js
@@ -29,8 +29,6 @@ const main = async () => {
     const halfWidth = radius - abs(ROW - y)
     if(halfWidth > 0) {
       fillRow(x, halfWidth);
-    }else {
-      console.log("Skip");
     }
   }
 
diff --git a/2022/15/index2.js b/2022/15/index2.js
new file mode 100644
index 0000000..373927d
--- /dev/null
+++ b/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();