number-of-1-bits py3

0191_number-of-1-bits/README.md

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+Write a function that takes an unsigned integer and returns the number of '1' bits it has (also known as the [Hamming weight](http://en.wikipedia.org/wiki/Hamming_weight)).
+
+**Note:**
+
+*   Note that in some languages, such as Java, there is no unsigned integer type. In this case, the input will be given as a signed integer type. It should not affect your implementation, as the integer's internal binary representation is the same, whether it is signed or unsigned.
+*   In Java, the compiler represents the signed integers using [2's complement notation](https://en.wikipedia.org/wiki/Two%27s_complement). Therefore, in **Example 3**, the input represents the signed integer. `-3`.
+
+**Example 1:**
+
+    Input: n = 00000000000000000000000000001011
+    Output: 3
+    Explanation: The input binary string 00000000000000000000000000001011 has a total of three '1' bits.
+    
+
+**Example 2:**
+
+    Input: n = 00000000000000000000000010000000
+    Output: 1
+    Explanation: The input binary string 00000000000000000000000010000000 has a total of one '1' bit.
+    
+
+**Example 3:**
+
+    Input: n = 11111111111111111111111111111101
+    Output: 31
+    Explanation: The input binary string 11111111111111111111111111111101 has a total of thirty one '1' bits.
+    
+
+**Constraints:**
+
+*   The input must be a **binary string** of length `32`.
+
+**Follow up:** If this function is called many times, how would you optimize it?
+
+https://leetcode.com/problems/number-of-1-bits

0191_number-of-1-bits/python3/solution.py

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+class Solution:
+    def hammingWeight(self, n: int) -> int:
+        count = 0
+        
+        while n:
+            count += 1 if n & 1 == 1 else 0
+            n >>= 1
+        
+        return count