Sword finger offer 50. the first character that appears only once

Title Description

Problem analysis

1. Use arrays to store , Different character elements are stored in different positions , Add one to the repeated character elements
2. The last part for Loop traversal operation pair subtraction a Value of character , Judge whether the value on a bit is one , If it is one, it means that the character only appears once

Code instance

class Solution {
    
    public char firstUniqChar(String s) {
    
        int[] count = new int[26];
        for(int i = 0;i < arr.length();i++){
    
        	char c = s.charAt(i);
        	count[c - 'a']++;
        }
        for(int i = 0;i < arr.length();i++){
    
        	char c = s.chaAt(i);
        	if(count[c - 'a'] == 1){
    
        		return c;
        	}
        }
        return ' ';
    }
}