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]
}
​