Merge pull request doocs#107 from ashwek/evalRPN

0150 Evaluate Reverse Polish Notation - Python

Author: yanglbme

solution/0150.Evaluate Reverse Polish Notation/Solution.py

@@ -0,0 +1,18 @@
+import operator as op
+
+class Solution:
+    def evalRPN(self, tokens):
+        """
+        :type tokens: list[str]
+        :rtype: int
+        """
+        stack = []
+        Opr = {"+":op.add, "-":op.sub, "*":op.mul, "/":op.truediv}
+        
+        for i in tokens:
+            if i in Opr:
+                stack.append( int( Opr[i](stack.pop(-2), stack.pop(-1)) ) )
+            else:
+                stack.append(int(i))
+        
+        return stack[0]