[chapse57] Week 3 (#2722)

* Add contains-duplicate solution

* [chapse57] Week 1

* fix: add final newline

* [chapse57] Week 2

* [chapse57] Week 2 - Group Anagrams

* fix: add final newline

* [chapse57] Week 3

* [chapse57] Week 3 - Number of 1 Bits

Author: chapse57

climbing-stairs/chapse57.py

@@ -0,0 +1,21 @@
+class Solution(object):
+    def climbStairs(self, n):
+        """
+        :type n: int
+        :rtype: int
+        """
+
+
+        if n == 1:
+            return 1
+        if n == 2:
+            return 2
+        a = 1
+        b = 2                
+
+        for i in range(n - 2):   
+            c = a + b
+            a = b
+            b = c
+        return c
+        

number-of-1-bits/chapse57.py

@@ -0,0 +1,9 @@
+class Solution(object):
+    def hammingWeight(self, n):
+        """
+        :type n: int
+        :rtype: int
+        """
+        return bin(n).count("1")
+
+