class Solution(object):
def evalRPN(self, tokens):
"""
:type tokens: List[str]
:rtype: int
"""
stack = []
ops = ["+","-","*","/"]
for i in tokens:
if i in ops:
if i == '+':
op2 = stack.pop()
op1 = stack.pop()
num = int(op1) + int(op2)
stack.append(num)
if i == '-':
op2 = stack.pop()
op1 = stack.pop()
num = int(op1) - int(op2)
stack.append(num)
if i == '*':
op2 = stack.pop()
op1 = stack.pop()
num = int(op1) * int(op2)
stack.append(num)
if i == '/':
op2 = stack.pop()
op1 = stack.pop()
num = int(op1) / int(op2)
stack.append(num)
else:
stack.append(i)
return stack[0]
class Solution:
def evalRPN(self, tokens):
"""
:type tokens: List[str]
:rtype: int
"""
stack = list()
oper = ['+', '-', '*', '/']
for char in tokens:
if char not in oper:
stack.append(int(char))
else:
top1 = stack.pop()
top2 = stack.pop()
if char == '+':
stack.append(top2 + top1)
elif char == '-':
stack.append(top2 - top1)
elif char == '*':
stack.append(top2 * top1)
elif char == '/':
stack.append(int(top2 / top1))
return stack.pop()
s = Solution()
t = ["2", "1", "+", "3", "*"]
t2 =["10","6","9","3","+","-11","*","/","*","17","+","5","+"]
print s.evalRPN(t2)
