(Python)NEXTPERM in IARCSJUD - Getting WA

help
1

Problem:

Algorithm:

  1. Loop from second last character to first character.
  2. Check if a lexicographically larger character exists after each character.
  3. If yes, swap character with smallest character present after it which is larger than it.
  4. Sort the characters after swapped character in non-decreasing order.

Code:

def next_perm(strr):
    strr=list(strr)
    n=len(strr)
    ck=0
    for i in range(-2, -1*(n+1), -1):
        tmp=strr[i]
        for i2 in range(i+1, 0, 1):
            if strr[i2]>tmp:
                strr[i2], strr[i] = strr[i], strr[i2]
                ck=1
                strr[i+1::]=sorted(strr[i+1::])
        if ck:
            break
    return strr
n, k = map(int, input().split())
for i in range(k):
    a=input().split()
    x=next_perm(a)
    for ix in range(len(x)-1):
        print(x[ix], end=' ')
    print(x[-1])

I am getting AC in 2 tasks, WA in other 9. Why?

And when I store numbers as int instead of string, my solution is able to pass 9 tasks. Why does that make a difference?!