feat: counting bits

Author: gwbaik9717

counting-bits/gwbaik9717.js

@@ -0,0 +1,24 @@
+// Time complexity: O(n)
+// Space complexity: O(n)
+
+/**
+ * @param {number} n
+ * @return {number[]}
+ */
+var countBits = function (n) {
+  const dp = Array.from({ length: n + 1 }, () => 0);
+
+  if (n === 0) {
+    return dp;
+  }
+
+  dp[1] = 1;
+
+  for (let i = 2; i <= n; i++) {
+    const k = Math.floor(Math.log2(i));
+
+    dp[i] = 1 + dp[i - Math.pow(2, k)];
+  }
+
+  return dp;
+};