题解 | #判断字符是否唯一#

import java.util.*;


public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param str string字符串 
     * @return bool布尔型
     */
    public boolean isUnique (String str) {
        // write code here
        int[] lower = new int[26];
        int[] upper = new int[26];
        char[] arr = str.toCharArray();
        for (int i = 0; i < arr.length; i++){
            if (Character.isUpperCase(arr[i])){
                if (upper[arr[i] - 'A'] == 1){
                    return false;
                }else{
                    upper[arr[i] - 'A'] = 1;
                }
            }else {
                if (lower[arr[i] - 'a'] == 1){
                    return false;
                }else {
                    lower[arr[i] - 'a'] = 1;
                }
            }
        }
        return true;
    }
}