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Java Array Exercises: Find all combination of four elements of a given array whose sum is equal to a given value

Java Array: Exercise-43 with Solution

Write a Java program to find all combination of four elements of a given array whose sum is equal to a given value.

Pictorial Presentation:

Java Array Exercises: Find all combination of four elements of an given array whose sum is equal to a given value

Sample Solution:

Java Code:

import java.util.*;
import java.lang.*;
public class Main
{
   public static void main (String[] args) 
    {  
      int nums[] = {10, 20, 30, 40, 1, 2};
      int n = nums.length;
      // given value
      int s = 53;
       System.out.println("Given value: "+s);
        System.out.print("Combination of four elements:");  
        // Find other three elements after fixing first element
        for (int i = 0; i < n - 3; i++) 
        {
          // Find other two elements after fixing second element
            for (int j = i + 1; j < n - 2; j++) 
            {
           // Find the fourth element after fixing third element    
              for (int k = j + 1; k < n - 1; k++) 
                {
            // find the fourth
                    for (int l = k + 1; l < n; l++) 
                    {
                        if (nums[i] + nums[j] + nums[k] + nums[l] == s) 
                            System.out.print("\n"+nums[i]+" "+nums[j]+" "+nums[k] 
                                                                 +" "+nums[l]);
                    }
                }
            }
    }
  }
}

Sample Output:

                                                                              
Given value: 53
Combination of four elements:
10 40 1 2
20 30 1 2

Flowchart:

Flowchart: Find all combination of four elements of an given array whose sum is equal to a given value

Visualize Java code execution (Python Tutor):


Java Code Editor:

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Previous: Write a Java program to segregate all 0s on left side and all 1s on right side of a given array of 0s and 1s.
Next: Write a Java program to count the number of possible triangles from a given unsorted array of positive integers.

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Java: Tips of the Day

Different between parseInt() and valueOf() in java?

Well, the API for Integer.valueOf(String) does indeed say that the String is interpreted exactly as if it were given to Integer.parseInt(String). However, valueOf(String) returns a new Integer() object whereas parseInt(String) returns a primitive int.

If you want to enjoy the potential caching benefits of Integer.valueOf(int), you could also use this eyesore:

Integer k = Integer.valueOf(Integer.parseInt("123"))

Now, if what you want is the object and not the primitive, then using valueOf(String) may be more attractive than making a new object out of parseInt(String) because the former is consistently present across Integer, Long, Double, etc.

Ref: https://bit.ly/3vRuIPY