[Solved] First Letter to Appear Twice LeetCode Contest Problem
![[Solved] First Letter to Appear Twice LeetCode Contest Problem](https://realcoder.techss24.com/wp-content/uploads/2022/07/Solved-First-Letter-to-Appear-Twice-LeetCode-Contest-Problem.png "[Solved] First Letter to Appear Twice LeetCode Contest Problem")
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. First Letter to Appear Twice LeetCode Contest…