First Unique Character in a String
Given a string s, find the first non-repeating character in it and return its index. If it does not exist, return -1.
Example 1:
Input: s = "leetcode"
Output: 0
Example 2:
Input: s = "loveleetcode"
Output: 2
Example 3:
Input: s = "aabb"
Output: -1
Constraints:
1 <= s.length <= 105
s consists of only lowercase English letters.
思路一:用长度为 26 的数组存储字符出现过的次数,最后遍历字符串,第一次出现次数为 1 的字符就是求解
public int firstUniqChar(String s) {
int[] counts = new int[26];
for (int i = 0; i < s.length(); i++) {
counts[s.charAt(i) - 'a']++;
}
for (int i = 0; i < s.length(); i++) {
if (counts[s.charAt(i) - 'a'] == 1) {
return i;
}
}
return -1;
}
标签:return,int,Example,Output,easy,387,Input,counts,leetcode
From: https://www.cnblogs.com/iyiluo/p/17025801.html