Bài 4

#Khoi tao string bat ki.
string = 'abcdcba'
"""
Thuat toan su dung if:
    Buoc 1: Check xem do dai string la so le hay khong.
    Buoc 2: Neu la so le thi check xem nua phia truoc co nguoc lai nua phia sau khong.
"""
    
if((len(string) % 2) == 1):
    if(string[len(string) // 2 -1::-1] == string[len(string) // 2 + 1 :] ):
        print(string + " la palindrome")
    else:
        print(string + " khong la palindrome")
else:
    print(string + " khong la palindrome")