LETTERS CYCLIC SHIFT

• Problem Description

  
  "You are given a non-empty string s consisting of lowercase English letters. You have to pick exactly one non-empty substring of s and shift all its letters 'z' 'y' 'x' 'b' 'a' 'z'. In other words, each character is replaced with the previous character of English alphabet and 'a' is replaced with 'z'.
  What is the lexicographically minimum string that can be obtained from s by performing this shift exactly once?
  
  Input
  The only line of the input contains the string s (1<|s|<100000) consisting of lowercase English letters.
  
  Output
  Print the lexicographically minimum string that can be obtained from s by shifting letters of exactly one non-empty substring.
  
  Note
  String s is lexicographically smaller than some other string t of the same length if there exists some 1i|s|, such that s1=t1,s2=t2,...,si-1=ti-1, and si<ti."
  

• CODING ARENA

• #include <stdio.h>

  #include <string.h>

  int main()

  {

    char s[100001];

    int i,k=0;

    scanf("%s",s);

    //l=strlen(a);

    for(i=0;s[i]!='\0';i++)

     if(s[i]!='a')

      break;

    for(;s[i]!='\0';i++) 

    {

      if(s[i]=='a')

        break;

      s[i]--;

      k++;

    }

    if(!k)

      s[strlen(s)-1]='z';

    puts(s);

    return 0;

  }

  
  

  /*

  int main()

  {

    char *shiftstr(char str[],int offset)

    {

      unsigned int i;

      for(i=0;str!='\0';i++)

      {

        str[i]+=offset;

      }

      return str;

    }

  return 0;

  }*/

• Test Case 1

  
  Input (stdin)

  codeforces
  
  

  Expected Output

  bncdenqbdr

• Test Case 2

  
  Input (stdin)

  srmulc
  
  

  Expected Output

  rqltkb