Question

How to perform binary search on ArrayList in Java

Answer 1

package javaapplication1;

import java.util.ArrayList;
import java.util.Collections;

public class JavaApplication1 {

    public static void main(String[] args) {

        ArrayList arrList = new ArrayList();

        arrList.add("132");
        arrList.add("431");
        arrList.add("134");
        arrList.add("236");
        arrList.add("364");
        arrList.add("489");
        arrList.add("298");

        // First we need to sort the ArrayList
        Collections.sort(arrList);
        System.out.println(arrList);

        // Search an element using binarySearch
        int index = Collections.binarySearch(arrList, "364");

        System.out.println();
        System.out.println("Element found at index : " + index);
  }
}
  
/*
run:

[132, 134, 236, 298, 364, 431, 489]

Element found at index : 4

*/

 

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