README.md

First letter to appear twice

Problem link

Solutions

Solution.cpp

// https://leetcode.com/problems/first-letter-to-appear-twice

class Solution {
 public:
  char repeatedCharacter(string s) {
    set<char> ss;
    for (char c : s) {
      if (ss.count(c)) return c;
      ss.insert(c);
    }
    return ' ';
  }
};

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