LeetCode 387 First Unique Character in a String

Problem:

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

Examples:

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

Summary:

找到字符串中第一个独一无二的字符。

Analysis:

用Hash表记录字符串中字符出现的次数，后遍历字符串，找到第一个出现次数为1的字符，返回其位置。

1 class Solution { 2 public: 3 int firstUniqChar(string s) { 4 int len = s.size(), ch[26] = {0}; 5 6 for (int i = 0; i < len; i++) { 7 int tmp = s[i] - 'a'; 8 ch[tmp]++; 9 } 10 11 for (int i = 0; i < len; i++) { 12 int tmp = s[i] - 'a'; 13 if (ch[tmp] == 1) { 14 return i; 15 } 16 } 17 18 return -1; 19 } 20 };

 

转载于:https://www.cnblogs.com/VickyWang/p/6009776.html

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