solve(w14): 338. Counting Bits (update)

Author: seungriyou

counting-bits/seungriyou.py

@@ -3,7 +3,7 @@
 from typing import List
 
 class Solution:
-    def countBits(self, n: int) -> List[int]:
+    def countBits1(self, n: int) -> List[int]:
         """
         [Complexity]
             - TC: O(n)
@@ -43,3 +43,17 @@ def countBits(self, n: int) -> List[int]:
             dp[i] = dp[i - offset] + 1
 
         return dp
+
+    def countBits(self, n: int) -> List[int]:
+        """
+        [Complexity]
+            - TC: O(n)
+            - SC: O(n)
+        """
+
+        dp = [0] * (n + 1)
+        for i in range(1, n + 1):
+            # dp[i] = dp[i // 2] + (i % 2)
+            dp[i] = dp[i >> 1] + (i & 1)
+
+        return dp