题解 | #密码验证合格程序#

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        String input = null;
        while((input = reader.readLine()) != null){
            if(input.length() < 8){
                System.out.println("NG");
            }else{
                int c1 = 0, c2 = 0, c3 = 0, c4 = 0;
                char[] c = input.toCharArray();
                for(int i = 0; i < c.length; i++){
                    if(c[i] >= 'a' && c[i] <= 'z'){
                        c1 = 1;
                    }
                    else if(c[i] >= 'A' && c[i] <= 'Z'){
                        c2 = 1;
                    }
                    else if(c[i] >= '0' && c[i] <= '9'){
                        c3 = 1;
                    }
                    else{
                        c4 = 1;
                    }
                    if(c1+c2+c3+c4 >= 3) break;
                }
                if(c1+c2+c3+c4 >= 3 && repeat(input)){
                    System.out.println("OK");
                }else{
                    System.out.println("NG");
                }
            }
        }

    }

    // 判断是否有重复字串
    public static boolean repeat(String s){
        int n1 = s.length();
        int mid = s.length()/2;
        for(int len = 3; len <= mid; len++){
            for(int i = 0; i <= n1-len; i++){
                String s1 = s.substring(0, i); // 前半部分字符串
                String s2 = s.substring(i, i+len); // 要判断的字符串
                String s3 = s.substring(i+len); // 后半部分字符串
                if(s1.contains(s2) || s3.contains(s2)){ // 判断是否包含s2这个子串
                    return false; // 有重复字符
                }
            }
        }
        return true;
    } 
}