这个swap给我干沉默了

def calm(a,b,op):
    a,b = b,a
    if op == "+":
        return a+b
    elif op == "-":
        return a-b
    elif op == "*":
        return a*b
    elif op == "/":
        return a/b

l = input().split()
operator = "+-*/"
stack = [0]*10000
top = -1
for i in l:
    if i not in operator:
        top+=1
        stack[top] = float(i)
    else:
        a = stack[top]
        top-=1
        b = stack[top]
        top-=1
        top+=1
        stack[top]=calm(a,b,i)

print("%.2f" %stack[top])

s = input()
st = [0]* 1000
top = -1
s = s.split()
temp = 0

for i in range(len(s)):
    if s[i] >= '0' and s[i] <= '9':
        top = top + 1
        st[top] = int(s[i])
    
    elif s[i] == '+':
        temp = st[top - 1] + st[top]
        top = top - 1
        st[top] = temp
    
    elif s[i] == '-':
        temp = st[top - 1] - st[top]
        top = top - 1
        st[top] = temp
    
    elif s[i] == '*':
        temp = st[top - 1]* st[top]
        top = top - 1
        st[top] = temp
    
    elif s[i] == '/':
        temp = st[top - 1]/ st[top]
        top = top - 1
        st[top] = temp
    
print("%.2f" % st[0])

def calc(a,b,op):
    if op=='+':
        return a+b
    if op=='-':
        return a-b
    if op=='*':
        return a*b
    if op=='/':
        return a/b

s=input()
st=[0]*1000
top=-1
t=0

for i in range(len(s)):
    if '0'<=s[i]<='9':
        t=t*10+int(s[i])
    elif s[i]==' ':
        top+=1
        st[top]=t
        t=0
    else:
        b=st[top]
        top-=1
        a=st[top]
        top-=1
        t=calc(a,b,s[i])
top+=1
st[top]=t
    
print("%.2f"%st[0])  #对①空结果保留两位小数

s=input() st=[0]1000 top=-1 x=0 for i in range(len(s)): if "0"<=s[i]<="9": x=x10+int(s[i]) elif s[i]" ": top+=1 st[top]=x x=0 else: num1=st[top] top-=1 num2=st[top] top-=1 if s[i]"+": x=num2+num1 elif s[i]"-": x=num2-num1 elif s[i]"": x=num2num1 elif s[i]=="/": x=num2/num1 print("%.2lf"%x)