solution: 2025/4

Signed-off-by: Alix von Schirp <github@avonschirp.bootmedia.de>

src/2025/4/1/index.ts

@@ -0,0 +1,35 @@
+export default async function runner(inputPath: string){
+  const input = (await Bun.file(inputPath).text()).trimEnd();
+
+  let accessible = 0;
+
+  input.split("\n").map(value => value.trim()).forEach((line, lineIndex, lineArray) => {
+    line.split("").forEach((char, charIndex, charArray) => {
+      if(char === ".") {
+        return;
+      }
+
+      let touch = 0;
+      for(let xOffset = -1; xOffset<2; xOffset++) {
+        for (let yOffset = -1; yOffset<2; yOffset++) {
+          if(xOffset === 0 && yOffset === 0) continue;
+          let x = charIndex+xOffset;
+          let y = lineIndex+yOffset;
+          if(x<0 || y<0 || y>=lineArray.length || x>=charArray.length) {
+            continue;
+          }
+          if((lineArray[y]?.charAt(x) ?? "") === "@"){
+            touch++;
+          }
+        }
+      }
+      if(touch<4) {
+        accessible++;
+        return;
+      }
+
+    })
+  })
+
+  console.log(accessible);
+}

src/2025/4/2/index.ts

@@ -0,0 +1,46 @@
+export default async function runner(inputPath: string) {
+  let input = (await Bun.file(inputPath).text()).trimEnd();
+
+
+  let accessible = 0;
+  let remove = 0;
+  do {
+    accessible = 0;
+    let newInput = ""
+    input.split("\n").map(value => value.trim()).forEach((line, lineIndex, lineArray) => {
+      line.split("").forEach((char, charIndex, charArray) => {
+        if (char === ".") {
+          newInput = newInput + ".";
+          return;
+        }
+
+        let touch = 0;
+        for (let xOffset = -1; xOffset < 2; xOffset++) {
+          for (let yOffset = -1; yOffset < 2; yOffset++) {
+            if (xOffset === 0 && yOffset === 0) continue;
+            let x = charIndex + xOffset;
+            let y = lineIndex + yOffset;
+            if (x < 0 || y < 0 || y >= lineArray.length || x >= charArray.length) {
+              continue;
+            }
+            if ((lineArray[y]?.charAt(x) ?? "") === "@") {
+              touch++;
+            }
+          }
+        }
+        if (touch < 4) {
+          accessible++;
+          remove++;
+          newInput = newInput + "."
+          return;
+        }
+        newInput = newInput + "@"
+      })
+      newInput = newInput + "\n"
+    })
+    input = newInput
+  } while (accessible !== 0)
+
+
+  console.log(remove);
+}