First Letter to Appear Twice - Practice Coding | SlaveCode
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2351. First Letter to Appear Twice
Easy
10 Points
Hash Table
String
Bit Manipulation
Counting
Given a string s consisting of lowercase English letters, return the first letter to appear twice.
Note:
Examples
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.
2351. First Letter to Appear Twice
Easy
10 Points
Hash Table
String
Bit Manipulation
Counting
Given a string s consisting of lowercase English letters, return the first letter to appear twice.
Note:
Examples
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'.