二进制中有多少个1

yingl · yingl · commit ab8fa346109d · 2016-08-04T14:14:12.000+08:00
diff --git a/count_1_in_binary.py b/count_1_in_binary.py
@@ -0,0 +1,14 @@
+# -*- coding: utf-8 -*-
+
+class Solution:
+    # @param num: an integer
+    # @return: an integer, the number of ones in num
+    def countOnes(self, num):
+        # write your code here
+        ret = 0
+        num &= 0xffffffff
+        while num != 0:
+            if num & 1:
+                ret += 1
+            num >>= 1
+        return ret
