content: package codingquestions.leetcode;
  
  /*
  1323. Maximum 69 Number
  Solved
  Easy
  Topics
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  Companies
  Hint
  You are given a positive integer num consisting only of digits 6 and 9.
  
  Return the maximum number you can get by changing at most one digit (6 becomes 9, and 9 becomes 6).
  
   
  
  Example 1:
  
  Input: num = 9669
  Output: 9969
  Explanation: 
  Changing the first digit results in 6669.
  Changing the second digit results in 9969.
  Changing the third digit results in 9699.
  Changing the fourth digit results in 9666.
  The maximum number is 9969.
  Example 2:
  
  Input: num = 9996
  Output: 9999
  Explanation: Changing the last digit 6 to 9 results in the maximum number.
  Example 3:
  
  Input: num = 9999
  Output: 9999
  Explanation: It is better not to apply any change.
   
  
  Constraints:
  
  1 <= num <= 104
  num consists of only 6 and 9 digits.
  */
  class Maximum69Number {
      public int maximum69Number (int num) {
          String s_num = Integer.toString(num);
          for(int i = 0; i < s_num.length(); i++){
              if(s_num.charAt(i) == '6'){
                  s_num = s_num.substring(0, i) + '9' + s_num.substring(i + 1);
                  break;
              }
          }
          return Integer.parseInt(s_num);
      }
  }
  