feat: Add solution for LeetCode problem 338

Author: WhiteHyun

counting-bits/WhiteHyun.swift

@@ -0,0 +1,27 @@
+//  
+//  338. Counting Bits
+//  https://leetcode.com/problems/counting-bits/description/
+//  Dale-Study
+//  
+//  Created by WhiteHyun on 2024/05/19.
+//  
+
+final class Solution {
+
+  // MARK: - Time Complexity: O(n), Space Complexity: O(n)
+
+  func countBits(_ n: Int) -> [Int] {
+    var array: [Int] = .init(repeating: 0, count: n + 1)
+    for i in stride(from: 1, through: n, by: 1) {
+      array[i] = array[i >> 1] + (i & 1)
+    }
+    return array
+  }
+
+  // MARK: - nonzeroBitCount
+
+  func countBits2(_ n: Int) -> [Int] {
+    return (0...n).map(\.nonzeroBitCount)
+  }
+
+}