Package g2301_2400.s2351_first_letter_to_appear_twice

Class Solution

java.lang.Object
g2301_2400.s2351_first_letter_to_appear_twice.Solution
public class Solution extends java.lang.Object
2351 - First Letter to Appear Twice.

Easy

Given a string s consisting of lowercase English letters, return the first letter to appear twice.

Note:

  • A letter a appears twice before another letter b if the second occurrence of a is before the second occurrence of b.
  • s will contain at least one letter that appears twice.

Example 1:

Input: s = “abccbaacz”

Output: “c”

Explanation:

The letter ‘a’ appears on the indexes 0, 5 and 6.

The letter ‘b’ appears on the indexes 1 and 4.

The letter ‘c’ appears on the indexes 2, 3 and 7.

The letter ‘z’ appears on the index 8.

The letter ‘c’ is the first letter to appear twice, because out of all the letters the index of its second occurrence is the smallest.

Example 2:

Input: s = “abcdd”

Output: “d”

Explanation:

The only letter that appears twice is ‘d’ so we return ‘d’.

Constraints:

  • 2 <= s.length <= 100
  • s consists of lowercase English letters.
  • s has at least one repeated letter.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Solution()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    char
    repeatedCharacter(java.lang.String s)
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • repeatedCharacter

      public char repeatedCharacter(java.lang.String s)