1、字符串中的第一个唯一字符
public class FirstUniqChar {
public int firstUniqChar(String s) {
int[] freq = new int[26];
for (int i = 0; i < s.length(); i++) freq[s.charAt(i) - 'a']++;
for (int i = 0; i < s.length(); i++) {
if (freq[s.charAt(i) - 'a'] == 1) return i;
}
return -1;
}
}