【HackerRank】Gem Stones

Gem Stones

John has discovered various rocks. Each rock is composed of various elements, and each element is represented by a lowercase latin letter from 'a' to 'z'. An element can be present multiple times in a rock. An element is called a 'gem-element' if it occurs at least once in each of the rocks.

Given the list of rocks with their compositions, display the number of gem-elements that exist in those rocks.

Input Format
The first line consists of N, the number of rocks.
Each of the next N lines contain rocks' composition. Each composition consists of lowercase letters of English alphabet.

Output Format
Print the number gem-elements that exist in those rocks.

Constraints
1 ≤ N ≤ 100
Each composition consists of only small latin letters ('a'-'z').
1 ≤ Length of each composition ≤ 100

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题解：

import java.io.*;
import java.util.*;
import java.math.*;


public class Solution {   
   static int[] Gem_Stones(String[] ele){
       int[] answer = new int[27];
       for(int i = 0;i < ele.length;i++){
           boolean[] has = new boolean[27];
           for(int j =0;j < ele[i].length();j++){
               char temp = ele[i].charAt(j);
               if(!has[temp-'a']){
                   answer[temp-'a']++;
                   has[temp-'a'] = true;
               }
           }
       }
       return answer;
   }


 public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int t;
        t = in.nextInt();
        String[] strings= new String[t];
        for(int i = 0;i < t;i++){
            strings[i] = in.next(); 
        }
        int[] answer = Gem_Stones(strings);
        int count = 0;
        for(int i = 0;i < answer.length;i++)
            if(answer[i]== t )
                count++;
        System.out.print(count);
   }
}