Given two strings s and t which consist of only lowercase letters.
String t is generated by random shuffling string s and then add one more letter at a random position.
Find the letter that was added in t.
Example:
Input:
s = "abcd"
t = "abcde"
Output:
e
Explanation:
'e' is the letter that was added.
一刷
题解：
方法一：词频统计
class Solution {
public char findTheDifference(String s, String t) {
int[] freq = new int[26];
for(int i=0; i<s.length(); i++){
freq[s.charAt(i) - 'a']++;
}
for(int i=0; i<t.length(); i++){
freq[t.charAt(i) - 'a']--;
if(freq[t.charAt(i) - 'a']<0) return t.charAt(i);
}
return 'a';
}
}
方法二： XOR
public char findTheDifference(String s, String t) {
int n = t.length();
char c = t.charAt(n - 1);
for (int i = 0; i < n - 1; ++i) {
c ^= s.charAt(i);
c ^= t.charAt(i);
}
return c;
}
