387.leetcode First Unique Character in a String(easy)[统计字符串字符次数]

Given a string, find the first non-repeating character in it and return it's index. If it doesn't exist, return -1.

Examples:

s = "leetcode"return 0.s = "loveleetcode",return 2.

题目要找第一个没有重复的字符，那么首先扫描一遍string存放每个字符出现的次数，再对string扫描一遍，如果次数为1那么就返回其index

class Solution {public:    int firstUniqChar(string s) {        //题目要找第一个没有重复的字符，那么首先扫描一遍string存放每个字符出现的次数，再对string扫描一遍，如果次数为1那么就返回其index        int n = s.length();        if(n<=0) return -1;        if(n == 1) return 0;        int sta[26];        memset(sta,0,sizeof(sta));        for(int i=0;i<n;i++)            sta[s[i]-'a']++;        for(int i=0;i<n;i++)        {            if(sta[s[i]-'a']==1)               return i;        }        return -1;    }};