day 8 done

08/index.ts

@@ -0,0 +1,144 @@
+import fs from "node:fs";
+import { printTime, now } from "../util";
+
+type Coord = [number, number];
+
+const test = false;
+
+const data = fs.readFileSync(
+  test ? "./inputs/testinput" : "./inputs/input",
+  "utf8"
+);
+
+let timer = now.instant();
+console.log(
+  "part one:",
+  Object.entries(
+    data
+      .split("\n")
+      .slice(0, -1)
+      .reduce((m, curr, row) => {
+        curr.split("").forEach((v, col) => {
+          if (v !== ".") {
+            m[v] = m[v] ? [...m[v], [row, col]] : [[row, col]];
+          }
+        });
+        return m;
+      }, {} as Record<string, Array<Coord>>)
+  )
+    .map(([_, locations]) => {
+      return locations.reduce((antinodes, curr, i, array) => {
+        return [
+          ...antinodes,
+          ...array.slice(i + 1).reduce((total, next) => {
+            return [
+              ...total,
+              [
+                curr[0] - Math.abs(curr[0] - next[0]),
+                curr[1] > next[1]
+                  ? curr[1] + Math.abs(curr[1] - next[1])
+                  : curr[1] - Math.abs(curr[1] - next[1]),
+              ] as Coord,
+              [
+                next[0] + Math.abs(curr[0] - next[0]),
+                curr[1] < next[1]
+                  ? next[1] + Math.abs(curr[1] - next[1])
+                  : next[1] - Math.abs(curr[1] - next[1]),
+              ] as Coord,
+            ];
+          }, [] as Array<Coord>),
+        ];
+      }, [] as Array<Coord>);
+    })
+    .map((antinodes) => {
+      return antinodes.filter((antinode) => {
+        let maxWidth = test ? 12 : 50;
+        return !(
+          antinode[0] < 0 ||
+          antinode[1] < 0 ||
+          antinode[0] >= maxWidth ||
+          antinode[1] >= maxWidth
+        );
+      });
+    })
+    .flat() // merge the frequencies
+    // because arrays are not comparable, we need to filter out duplicates after strigifying them
+    .map((v) => JSON.stringify(v))
+    .reduce((total, v, i, a) => {
+      return a.indexOf(v) === i ? total + 1 : total;
+    }, 0),
+  printTime(now.instant().since(timer))
+);
+
+timer = now.instant();
+console.log(
+  "part two:",
+  Object.entries(
+    data
+      .split("\n")
+      .slice(0, -1)
+      .reduce((m, curr, row) => {
+        curr.split("").forEach((v, col) => {
+          if (v !== ".") {
+            m[v] = m[v] ? [...m[v], [row, col]] : [[row, col]];
+          }
+        });
+        return m;
+      }, {} as Record<string, Array<Coord>>)
+  )
+    .map(([_, locations]) => {
+      return locations.reduce((antinodes, curr, i, array) => {
+        return [
+          ...antinodes,
+          curr, // include the antennas themselves
+          ...array.slice(i + 1).reduce((total, next) => {
+            // draw the line north...
+            let localCurr = curr;
+            while (localCurr[0] > 0 && localCurr[1] > 0) {
+              let k = total.push([
+                localCurr[0] - Math.abs(localCurr[0] - next[0]),
+                localCurr[1] > next[1]
+                  ? localCurr[1] + Math.abs(localCurr[1] - next[1])
+                  : localCurr[1] - Math.abs(localCurr[1] - next[1]),
+              ]);
+              next = localCurr;
+              localCurr = total[k - 1];
+            }
+            return total;
+          }, [] as Array<Coord>),
+          ...array.slice(i + 1).reduce((total, next) => {
+            // ...and south
+            let localCurr = curr;
+            while (next[0] < (test ? 12 : 50) && next[1] < (test ? 12 : 50)) {
+              let k = total.push([
+                next[0] + Math.abs(localCurr[0] - next[0]),
+                localCurr[1] < next[1]
+                  ? next[1] + Math.abs(localCurr[1] - next[1])
+                  : next[1] - Math.abs(localCurr[1] - next[1]),
+              ]);
+              localCurr = next;
+              next = total[k - 1];
+            }
+            return total;
+          }, [] as Array<Coord>),
+        ];
+      }, [] as Array<Coord>);
+    })
+    .map((antinodes) => {
+      return antinodes.filter((antinode) => {
+        let maxWidth = test ? 12 : 50;
+        return !(
+          antinode[0] < 0 ||
+          antinode[1] < 0 ||
+          antinode[0] >= maxWidth ||
+          antinode[1] >= maxWidth
+        );
+      });
+    })
+    .flat()
+    .map((v) => JSON.stringify(v))
+    .reduce((total, v, i, a) => {
+      return a.indexOf(v) === i ? total + 1 : total;
+    }, 0),
+  printTime(now.instant().since(timer))
+);