문제 해설 추가

level-2/3-x-n-타일링.js

@@ -0,0 +1,18 @@
+//https://github.com/codeisneverodd/programmers-coding-test
+//더 좋은 풀이가 존재할 수 있습니다.
+//정답 1 - codeisneverodd
+function solution(n) {
+  if (n % 2 !== 0) return 0;
+
+  const getCount = n => {
+    const k = n / 2;
+    const count = [3, 11, ...Array(k - 2)];
+    const divider = 1000000007;
+    for (let i = 2; i < k; i++) {
+      count[i] = (4 * count[i - 1] - count[i - 2] + divider) % divider;
+    }
+    return count[count.length - 1];
+  };
+
+  return getCount(n);
+}

level-2/이진-변환-반복하기.js

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+//https://github.com/codeisneverodd/programmers-coding-test
+//더 좋은 풀이가 존재할 수 있습니다.
+//정답 1 - codeisneverodd
+function solution(s) {
+  const removeZero = s => {
+    const removed = s
+      .split('')
+      .filter(n => n !== '0')
+      .join('');
+    return { removed, count: s.length - removed.length };
+  };
+
+  const convertToBinary = (s, turnCount, removedCount) => {
+    if (s === '1') return [turnCount, removedCount];
+    const { removed, count } = removeZero(s);
+    return convertToBinary(removed.length.toString(2), turnCount + 1, removedCount + count);
+  };
+
+  return convertToBinary(s, 0, 0);
+}