Longest Common Pattern_LCPESY - Wrong Answer[[closed]]

link - https://www.codechef.com/problems/LCPESY
this as I understand it is a character counting problem, can anyone tell me why this is wrong?

# cook your dish here
for tc in range(int(input())):
    str1 = list(input())
    str2 = list(input())
    count = 0
    l = min(len(str1),len(str2))
    for i in range(l):
        if str1[i] == str2[i]:
            count += 1

Take the example of str 1 = bbc and str2 = aab. Your code will output 0, when the count is actually one. After sorting you cannot simply compare the corresponding indices. You have to try something else. In C++ I would use std::map<char, int>. I am not aware of the alternative in python.

[UPD]: Alternatively, you can use a frequency table. Declare two arrays of length 26, f1 and f2, and initialize all the elements as 0. Now traverse str1 and update the frequency of a character as f1[str1[i] - ‘a’]++. Similarly fill f2.

for i in range(26):
    count += min(f1[i], f2[i]);

should do the trick.

[UPD2]: The problem seems to have case sensitive characters, so you must make a frequency table of size 52.

got it! the case you gave cleared the question for me. Thanks.