Stack Discipline Target: 15s
RPN evaluation: numbers push, operators pop two and push result. Note: pop order is b, a (right operand first).
stack = []
for tok in tokens:
if tok in '+-*/':
b, a = stack.pop(), stack.pop()
if tok == '+': stack.append(a + b)
elif tok == '-': stack.append(a - b)
elif tok == '*': stack.append(a * b)
else: stack.append(int(a / b))
else:
stack.append(int(tok))Type it from memory. Go.