leetcode_gym/_problems/firstNonRepeatingChar.md

layout, title, last_solved, category, leetcode_url, status

layout	title	last_solved	category	leetcode_url	status
page	First Unque Char in String	2020-06-06	string	https://leetcode.com/problems/first-unique-character-in-a-string	Solved

Problem

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.

Solution

{% highlight python %}

def firstUniqChar(self, s: str) -> int:

if not s: return -1

dict = {}

# add to dict
for c in s:
    if c not in dict.keys():
        dict[c] = 1
    else:
        dict[c] = dict[c]+1

# find first char with count=1 and return it
for i, c in enumerate(s):
    if dict[c]==1:
        return i

return -1

{% endhighlight %}