389. Find the Difference

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LeetCode

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Problem

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"

Example 3:

Input: s = "a", t = "aa"
Output: "a"

Example 4:

Input: s = "ae", t = "aea"
Output: "a"

Code

class Solution {
    public char findTheDifference(String s, String t) {
        int[] count = new int[26];
        for(char c : s.toCharArray()){
            count[c - 'a']++;
        }

        for(char c : t.toCharArray()){
            if(--count[c - 'a'] < 0){
               return c;
            }
        }

        return ' ';
    }
}