LeetCode 387. 字符串中的第一个唯一字符(哈希表)

class Solution {
public:
    int firstUniqChar(string s) {
        if (s.size() <= 0) {
            return -1;
        }
        map<int, int> smap;
        for (char ch : s) {
            smap[ch]++;
        }
        for (int i = 0; i < s.size(); i++) {
            if (smap[s[i]] == 1) {
                return i;
            }
        }
        return -1;
    }
};

class Solution {
public:
    int firstUniqChar(string s) {
        int map[26] = {0};
        for (int i = 0; i < s.size(); i++) {
            map[s[i] - 'a']++;
        }
        for (int i = 0; i < s.size(); i++) {
            if (map[s[i] - 'a'] == 1) {
                return i;
            }
        }
        return -1;
    }
};