【Leetcode】387. First Unique Character in a String

方法一：

思路：Map——O(nlogn)

public class Solution {    public int firstUniqChar(String s) {        int len = s.length();        Map<Character, Integer> map = new HashMap<Character, Integer>();        for (int i = 0; i < len; i++) {            if (map.containsKey(s.charAt(i)))                map.put(s.charAt(i), map.get(s.charAt(i)) + 1);            else                map.put(s.charAt(i), 1);        }        for (int i = 0; i < len; i++) {            if (map.get(s.charAt(i)) == 1)                return i;        }	    return -1;    }}
Runtime：137ms
方法二：
思路：数组——O(n)
public class Solution {    public int firstUniqChar(String s) {        int count[] = new int[26], len = s.length();        for (int i = 0; i < len; i++)         	count[s.charAt(i) - 'a']++;	   	for (int i = 0; i < len; i++)         	if (count[s.charAt(i) - 'a']== 1)         		return i;	    return -1;    }}
Runtime：23ms