387. First Unique Character in a String Easy 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. Note: You…

Description Find the first unique character in a given string. You can assume that there is at least one unique character in the string. Example For "abaccdeff", return 'b'. 解题:返回仅出现一次,并且排在最前面的那个元素,而不是返回第一个不同的元素,一开始理解错了.如果仅仅对于ASCII中的256个字符,可以用数组…

问题描述 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. Java算法实现 public class Solution { public int first…

题目标签:String, HashMap 题目给了我们一个 string,让我们找出 第一个 唯一的 char. 设立一个 hashmap,把 char 当作 key,char 的index 当作value. 遍历string,如果这个 char 没有在 map 里,说明第一次出现,存入 char,index:                    如果这个 char 已经在 map 里,说明不是第一次出现,而且我们不在乎这种情况,更新 char, -1. 遍历hashmap,把最小的 inde…

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. Note: You may assume the string contain only lowercase…

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. 分析:找出字符串中第一次出现且不重复的字符,返回其字符的下标,如果不存在就返回-1. 用hashMap进行求…

Problem: Given a string, find the first non-repeating character in it and return it's index. If it doesn't exist, return -1. Example: s = "leetcode" return 0. s = "loveleetcode", return 2. 本题的第一想法是开一个字母表计数器,遍历string s中的元素,并利用计数器对每一个字母计…

原题链接在这里:https://leetcode.com/problems/first-unique-character-in-a-string/ 题目: 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 = "lovele…

最近公司搬家了,有两天没写了,今天闲下来了,继续开始算法之路. leetcode的题目如下: 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. Note: Y…

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. Note: You may assume the string contain only lowerca…