389. Find the Difference

Easy

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.

解題

Runtime: 0 ms, faster than 100.00%

Memory Usage: 2.2 MB, less than 82.16%

func findTheDifference(s string, t string) byte {
    count := make([]int, 26)
    
    for i := 0; i < len(s); i++ {
        count[s[i] - 'a']++
    }
    
    for i := 0; i < len(t); i++ {
        if count[t[i]-'a'] == 0 { return t[i] }
        count[t[i]-'a']--
    }
    
    return t[0]
}