Created
March 21, 2023 07:20
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postfix = ['111', '2', '+', '33', '2', '**', '+', '1', '1', '*', '-'] | |
def is_number(num): | |
# quick way | |
return num[0] in '0123456789' | |
def eval_postfix(postfix): | |
stack = [] | |
for element in postfix: | |
if is_number(element): | |
stack.append(element) | |
else: | |
v1 = int(stack.pop()) | |
v2 = int(stack.pop()) | |
if element == '**': | |
v = v2 ** v1 | |
stack.append(v) | |
elif element == '*': | |
v = v2 * v1 | |
stack.append(v) | |
if element == '/': | |
v = v2 // v1 | |
stack.append(v) | |
if element == '+': | |
v = v2 + v1 | |
stack.append(v) | |
if element == '-': | |
v = v2 - v1 | |
stack.append(v) | |
return stack[0] | |
print(eval_postfix(postfix)) |
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