Lexicographically Smallest Non-Palindromic String - Amazon Top Interview Questions


Problem Statement :


You are given a lowercase alphabet string s that is a palindrome. Update one character such that s is no longer a palindrome and is lexicographically smallest.

Constraints

2 ≤ n ≤ 100,000 where n is the length of s

Example 1

Input
s = "racecar"

Output

"aacecar"

Explanation

We can change the first "r" to "a" to get the


Solution :



title-img 




                        Solution in C++ :

string solve(string s) {
    for (int i = 0; i < s.size() / 2; i++) {
        if (s[i] != 'a') {
            s[i] = 'a';
            return s;
        }
    }
    s[s.size() - 1] = 'b';
    return s;
}
                    




                        Solution in Python : 
                            
class Solution:
    def solve(self, s):
        s = list(s)
        n = len(s)
        for i in range(0, n // 2):
            if s[i] != "a":
                s[i] = "a"
                return "".join(s)
        s[n - 1] = "b"
        if n < 2:
            return "-1"
        else:
            return "".join(s)


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