如何通过char数组搜索String数组？

Question

I want to build a simple dictionary search program without using dictionary library. I want to search the string array if the string in array is equal to the char array. It should print the string and its index number. If there are 2 strings that are matching the char then it should print the first string and leave the after string

.eg String array["fine","rest","door","shine"] char character ['t','r','e','s']. the answer should be "rest" at index 1. and if the String rest is repeat then it should only print first one.

I tried to compare the string array and char array but its returning all the words of string array that matches char array.

String strArray[]=new String[4];
char chrArray[]=new char[4]; 
String value="";
char compare;
System.out.println("Enter the words :");
    for(int i=0;i<strArray.length;i++){
    strArray[i]=input.next();

    } 
    System.out.println("Enter the Characters :");
    for (int i = 0; i < chrArray.length; i++) {
        chrArray[i]=input.next().charAt(0);

    }

    for (int i = 0; i < strArray.length; i++) {
            if(strArray[i].length()==chrArray.length){
                 if(""+strArray[i]!=value){
               value="";
            }
        for (int j = 0; j < strArray[i].length(); j++) {

            for (int k = 0; k < chrArray.length; k++) {


                if(strArray[i].charAt(j)==chrArray[k]){
                value=value+strArray[i].charAt(j);   

                }
            }
            }
        }

}
        System.out.println(value);

The output should be the string from array that is equal to char array.

Answer 1

You can sort char array and then compare it using Arrays.equal . By sorting char array, there will be no need to use 2 for loops.

import java.util.Arrays;
import java.util.Scanner;

public class Bug {

        public static void main(String[] args) {
            String strArray[]=new String[4];
            char chrArray[]=new char[4];
            Scanner input = new Scanner(System.in);
            System.out.println("Enter the words :");
            for(int i=0;i<strArray.length;i++){
                strArray[i]=input.next();

            }
            System.out.println("Enter the Characters :");
            for (int i = 0; i < chrArray.length; i++) {
                chrArray[i]=input.next().charAt(0);

            }
            Arrays.sort(chrArray);

            for (int i = 0; i < strArray.length; i++) {
                char[] x = strArray[i].toCharArray();
                Arrays.sort(x);
                if(Arrays.equals(chrArray, x))
                {
                    System.out.println(strArray[i]);
                    break;
                }
            }
        }

 }

Answer 2

You could also create a Map<Character, Integer> to store counts for both the words and the characters, and compare each word character counts with the character counts. If both are equal, print it out.

Demo:

import java.util.Map;
import java.util.HashMap;

public class Example {
    private static final String[] words = {"fine", "rest", "door", "shine"};
    private static final char[] chars = {'t', 'r', 'e', 's'};

    /**
     * Initialise String character counts in a hashmap datastructure.
     * @param word The string word to iterate.
     * @return Hashmap of character -> counts.
     */
    private static Map<Character, Integer> getCharCounts(String word) {
        Map<Character, Integer> wordCounts = new HashMap<>();

        for (int i = 0; i < word.length(); i++) {
            Character character = word.charAt(i);

            // If key doesn't exist, initialise it
            if (!wordCounts.containsKey(character)) {
                wordCounts.put(character, 0);
            }

            // Increment count by 1
            wordCounts.put(character, wordCounts.get(character) + 1);
        }

        return wordCounts;
    }

    public static void main(String[] args) {     
        // Initialise character counts first
        Map<Character, Integer> charCounts = getCharCounts(String.valueOf(chars));

        for (int i = 0; i < words.length; i++) {
            Map<Character, Integer> wordCounts = getCharCounts(words[i]);

            // If Hashmaps are equal, then we have found a match
            if (wordCounts.equals(charCounts)) {
                System.out.println(words[i] + ", at index = " + i);
                break;
            }
        }
    }
}

Output:

rest, at index = 1