feat(leetcode): add No.397

Author: mickey0524

397.Integer-Replacement.py

@@ -0,0 +1,26 @@
+# https://leetcode.com/problems/integer-replacement/description/
+#
+# algorithms
+# Medium (30.67%)
+# Total Accepted:    34.5k
+# Total Submissions: 112.5k
+# beats 100.0% of python submissions
+
+
+class Solution(object):
+    def integerReplacement(self, n):
+        """
+        :type n: int
+        :rtype: int
+        """
+        res = 0
+        while n != 1:
+            if bin(n)[-1] == '0':
+                n = n >> 1
+            else:
+                if bin(n)[-2] == '1' and len(bin(n)) != 4:
+                    n += 1  # if '11' +1
+                else:
+                    n -= 1  # if '01' -1
+            res += 1
+        return res