Help me in solving DNASTORAGE problem

help
,
1

My issue

Cant solve

My code

# cook your dish here

Learning course: Strings using Python
Problem Link: DNA Storage Practice Problem in - CodeChef

2

@smitajha7701
plzz refer the following solution for better understanding

# cook your dish here
test_case = int(input())
for i in range(test_case):
    seq = int(input())
    string = input()
    iter = seq - int(seq/2)
    i = 0
    while(i<iter):
        if string[i] == '0' and string[i+1] == '0':
            string = string.replace('00','A', 1)
        elif string[i] == '0' and string[i+1] == '1':
            string = string.replace('01','T', 1)
        elif string[i] == '1' and string[i+1] == '0':
            string = string.replace('10','C', 1)
        elif string[i] == '1' and string[i+1] == '1':
            string = string.replace('11','G', 1)
        i += 1
    print(string)
3

Here is another Python Solution for DNA Storage

# cook your dish here
t = int(input())
for _ in range (t) :
    n = int(input())
    s = str(input())
    a = 0
    dna = ''
    for i in s :
        if s[a:a+2] == '00' :
            dna = dna + 'A'
        if s[a:a+2] == '01' :
            dna = dna + 'T'
        if s[a:a+2] == '10' :
            dna = dna + 'C'
        if s [a:a+2] == '11' :
            dna = dna + 'G'
        
        a = a + 2 
    print(dna)