C++ 代码

class Solution {
public:
    char firstNotRepeatingChar(string s) {
        int arr[122] = {0};
        for(int i = 0; i < s.size(); ++i)
            arr[s[i]]++;

        for(int i = 0; i < s.size(); ++i)
            if(arr[s[i]] == 1)  return s[i];

        return '#';
    }
};