refactor

src/2024/day02.js

@@ -1,32 +1,19 @@
+function isSafe(line) {
+  const result = line.map((num, i) => i > 0 && num - line[i - 1]).slice(1);
+  return (
+    result.every(num => num >= 1 && num <= 3) ||
+    result.every(num => num <= -1 && num >= -3)
+  );
+}
+
 export function part1(input) {
   const lines = input.split("\n").map(line => line.split(" ").map(Number));
-  const safe = lines.filter(line => {
-    const result = line
-      .map((num, i) => (i === 0 ? 0 : num - line[i - 1]))
-      .slice(1);
-    return (
-      result.every(num => num >= 1 && num <= 3) ||
-      result.every(num => num <= -1 && num >= -3)
-    );
-  });
-  return safe.length;
+  return lines.filter(isSafe).length;
 }
 
 export function part2(input) {
   const lines = input.split("\n").map(line => line.split(" ").map(Number));
-  const safe = lines.filter(line => {
-    for (let i = 0; i < line.length; i++) {
-      const newLine = line.slice();
-      newLine.splice(i, 1);
-      const result = newLine
-        .map((num, i) => (i === 0 ? 0 : num - newLine[i - 1]))
-        .slice(1);
-      if (
-        result.every(num => num >= 1 && num <= 3) ||
-        result.every(num => num <= -1 && num >= -3)
-      )
-        return true;
-    }
-  });
-  return safe.length;
+  return lines.filter(line => {
+    return line.map((x, i) => line.toSpliced(i, 1)).find(isSafe);
+  }).length;
 }