Today I have done leetcode's September LeetCoding Challenge with cpp.

September LeetCoding Challenge 25

Description

Find the Difference

You are given two strings s and t.

String t is generated by random shuffling string s and then add one more letter at a random position.

Return the letter that was added to t.

Example 1:

Input: s = "abcd", t = "abcde"
Output: "e"
Explanation: 'e' is the letter that was added.

Example 2:

Input: s = "", t = "y"
Output: "y"

Constraints:

• 0 <= s.length <= 1000
• t.length == s.length + 1
• s and t consist of lowercase English letters.

Solution

auto speedup = [](){
  cin.tie(nullptr);
  cout.tie(nullptr);
  ios::sync_with_stdio(false);
  return 0;
}();
class Solution {
public:
  char findTheDifference(string s, string t) {
    int count[26] = {};
    for(auto c : s) {
      count[c - 'a'] += 1;
    }
    for(auto c : t) {
      count[c - 'a'] -= 1;
    }
    for(int i = 0; i < 26; ++i) {
      if(count[i]) return i + 'a';
    }
    return 0;
  }
};

// Accepted
// 54/54 cases passed (0 ms)
// Your runtime beats 100 % of cpp submissions
// Your memory usage beats 87.58 % of cpp submissions (6.6 MB)