微软2016校园招聘在线笔试第二场 题目1 : Lucky Substrings

时间限制:10000ms

单点时限:1000ms

内存限制:256MB

描述

A string s is LUCKY if and only if the number of different characters in s is a fibonacci number. Given a string consisting of only lower case letters, output all its lucky non-empty substrings in lexicographical order. Same substrings should be printed once.

输入

A string consisting no more than 100 lower case letters.

输出

Output the lucky substrings in lexicographical order, one per line. Same substrings should be printed once.

样例输入

aabcd

样例输出

a
aa
aab
aabc
ab
abc
b
bc
bcd
c
cd
d

import java.util.HashSet;
import java.util.Scanner;
import java.util.TreeSet;

public class Main {
    public static HashSet<Integer> fibsetHashSet;
    static{
        fibsetHashSet= new HashSet<Integer>();
        fibsetHashSet.add(0);
        fibsetHashSet.add(1);
        fibsetHashSet.add(2);
        fibsetHashSet.add(3);
        fibsetHashSet.add(5);
        fibsetHashSet.add(8);
        fibsetHashSet.add(13);
        fibsetHashSet.add(21);
        fibsetHashSet.add(34);
        fibsetHashSet.add(55);
        fibsetHashSet.add(89);
    }
    public static boolean isFib(String sub){

        int count[]=new int[26]; //全是零

        if(sub.length()==0)return false;

        for(int i=0; i<sub.length(); i++){
            char a=sub.charAt(i);
            count[a-'a']+=1;
        }
        int diff=0;
        for( int i=0; i<26; ++i){
            if(count[i]!=0)++diff;
        }

        for( int i=0; i<26; ++i){
            if(!fibsetHashSet.contains(diff))return false; //如果不符合
        }
        return true;
    }
    public static void main(String args[]){
        Scanner scanner=new Scanner(System.in);
        String string=scanner.next();
        //String string="aabcd";
        TreeSet<String> set = new TreeSet<String>();

        int len=string.length();
        for(int i=0; i<len; i++){
            for(int j=i+1; j<=len; j++){
                String subString=string.substring(i, j);
                if(isFib(subString)){
                    set.add(subString);
                }
            }
        }
        for(String key: set){
            System.out.println(key);
        }
        //System.out.println(set);
    }
}