vector
class Solution {
public:
char firstUniqChar(string s) {
int len = s.size();
vector<int> c(26);
for(int i=0;i<len;++i){
c[s[i] - 'a']++;
}
for(int i=0;i<len;++i){
if(c[s[i] - 'a'] == 1)
return s[i];
}
return ' ';
}
};
unordered_map
class Solution {
public:
char firstUniqChar(string s) {
unordered_map<char,int> m;
for(auto &c:s){
m[c]++;
}
for(auto &c:s){
if(m[c] == 1)
return c;
}
return ' ';
}
};