1796. Second Largest Digit in a String.md

1796. Second Largest Digit in a String

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the first one in Biweekly Contest 48.

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Difficulty : Easy

Related Topics : String

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Given an alphanumeric string s, return the second largest numerical digit that appears in s, or -1 if it does not exist.

An alphanumeric string is a string consisting of lowercase English letters and digits.

Example 1:

Input: s = "dfa12321afd"
Output: 2
Explanation: The digits that appear in s are [1, 2, 3]. The second largest digit is 2.

Example 2:

Input: s = "abc1111"
Output: -1
Explanation: The digits that appear in s are [1]. There is no second largest digit.

Constraints:

• 1 <= s.length <= 500
• s consists of only lowercase English letters and/or digits.

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Solution

• mine
  • Java
    • Runtime: 1 ms, faster than 100.00%, Memory Usage: 39.3 MB, less than 100.00% of Java online submissions

      // O(N)time
      // O(N)space
      public int secondHighest(String s) {
          char[] arr = s.toCharArray();
          int size = 0;
          int[] count = new int[10];
          for(int i = 0; i < arr.length; i++){
              if(arr[i] >= 'a') continue;
      
              int t = arr[i] - '0';
              if(count[t] == 0) size++;
              count[t]++;
          }
          if(size < 2) return -1;
          int t = 2;
          for(int i = count.length - 1; i >= 0; i--){
              if(count[i] != 0){
                  t--;
              }
              if(t == 0) return i;
          }
          return 0;
      }
      

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