Help me in solving GCDISCOUNT problem

help
,
1

My issue

I have tried to code it as follows-
"def gcd(a,b):
# Find minimum of a and b
result=min(a,b)
while result:
if a%result==0 and b%result==0:
break
result-=1
# Return the gcd of a and b
return result

def initialgcd(lst):
gcdval=lst[0]
for i in lst[1:]:
gcdval=gcd(gcdval,i)
return gcdval

t=int(input())
for i in range(t):
n=int(input())
price=list(map(int,input().split()))
discounted=list(map(int,input().split()))

initialgcdval=initialgcd(price)
maxgcd=initialgcdval
for i in range(len(discounted)):
    temp=price[i]
    price[i]=discounted[i]
    gcd1=initialgcd(price)
    maxgcd=max(gcd1,maxgcd)
    price[i]=temp
    
print(maxgcd)"

But I don’t know the way to optimize it

My code

def gcd(a,b):
    # Find minimum of a and b
    result=min(a,b)
    while result:
        if a%result==0 and b%result==0:
            break
        result-=1
    # Return the gcd of a and b
    return result

def initialgcd(lst):
    gcdval=lst[0]
    for i in lst[1:]:
        gcdval=gcd(gcdval,i)
    return gcdval
    
t=int(input())
for i in range(t):
    n=int(input())
    price=list(map(int,input().split()))
    discounted=list(map(int,input().split()))
    
    initialgcdval=initialgcd(price)
    maxgcd=initialgcdval
    for i in range(len(discounted)):
        temp=price[i]
        price[i]=discounted[i]
        gcd1=initialgcd(price)
        maxgcd=max(gcd1,maxgcd)
        price[i]=temp
        
    print(maxgcd)

Problem Link: GCDISCOUNT Problem - CodeChef