Update solution 070 [Python3]

Author: chakyam

solution/070.Climbing Stairs/Solution.py

@@ -0,0 +1,14 @@
+class Solution:
+    def climbStairs(self, n):
+        """
+        :type n: int
+        :rtype: int
+        """
+        if n<3:
+            return n
+        res=[None]*(n+1)
+        res[1]=1
+        res[2]=2
+        for i in range(3,n+1):
+            res[i]=res[i-1]+res[i-2]
+        return res[n]