Merge pull request doocs#111 from zhanary/master

Upload two kind of methods to 0069 with python2

Author: yanglbme

solution/0069.sqrt-x/Solution.py

@@ -0,0 +1,18 @@
+# binary search [python2] - 40ms
+
+class Solution(object):
+    def mySqrt(self, x):
+        if x == 0:
+            return 0
+        
+        left = 0
+        right = x
+        while True:
+            mid = left + (right-left)/2
+            if (mid * mid > x):
+                right = mid - 1
+            else:
+                if (mid+1) * (mid+1) > x:
+                    return mid
+                left = mid + 1
+      

solution/0069.sqrt-x/Solution2.py

@@ -0,0 +1,9 @@
+# Newton's Method [python2] - 28ms
+
+class Solution(object):
+    def mySqrt(self, x):
+        r = x
+        while r * r > x:
+            r = (r + x/r)/2
+        
+        return r