387.求字符串中第一个独立存在的字符 First Unique Character in a String

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 letters.

public class Solution {
    public int FirstUniqChar(string s) {
        int index = -1;
        char[] chars = s.ToCharArray();
        char c = ' ';
        int length = chars.Length;
        Dictionary<char,int> d = new Dictionary<char,int>();
        for(int i =0;i<length;i++){
            c = chars[i];
            int v = 0;
            if(d.TryGetValue(c,out v)){
                d[c] = v + 1;                
            }else{
                d.Add(c,1);
            }
        }
        for(int i=0;i<length;i++){
            c = chars[i];
            if(d[c] == 1){
                index = i;
                break;
            }
        }
        return index;
    }
}

来自为知笔记(Wiz)