Arrays concept is touted among the most crucial yet significant concepts of the coding interview! From array types to reversing an array to merging arrays to finding the second largest number in an array, you will come across several sub-concept topics in an array. In Java, you may often come across the concept of merging two sorted arrays.
To merge the two sorted arrays in the Java language, you can use the predefined methods or can sort an array manually with the help of loops.
Well, if you are interested in learning more about this concept, then stick to this blog post till the end.
Let’s get started!
Merging two arrays in java – an overview
Merging two sorted arrays in the popular language Java is quite similar to the concatenation or combination of two arrays in the form of a single defined array object. We need to merge the two arrays in such a way that all of its elements will maintain their ideal order in a newly merged array.
All the elements in a first array may proceed to other elements in the given second array or in a newly merged array.
Take an example;
Int [] arr 1 = [ 1, 2, 3, 4, 5, 6 ] // first array
Int [] arr 2 = [ 7, 8, 9, 0] // second array
[ 1, 2, 3, 4, 5, 6, 7, 8, 9, 0 ] would be the resultant array in this case.
Ways of merging two sorted arrays
To merge two sorted arrays, you need to take into account the below-mentioned approaches. The noteworthy thing here is, that you can use these approaches in order to merge your arrays in an ideal way.
Conventional or manual method
Here, in this method, we may not be using a predefined method to merge the array. We are taking one array and then the second. Then, we are calculating the length of both present arrays.
We create another new array which has a length equal to the sum of lengths of the other two arrays. Now, we can start adding in a resulting array. As a result, we can get a resultant array, which would be the concatenation of the other two arrays.
Merging arrays using loop
In order to merge two arrays with the help of loops, you can assume the src 1 and the src2. Then you can declare any new variable which is given with the size of an array.
Copy the first array which is src 1 to the new array from the 0 to src 1. Then, copy the second array with the src1 length.
Java arraycopy () method
The Java arraycopy() method is generally considered the ideal system class method, which mainly belongs to java.lang package. This method copies a given array from any of the specified sources till its specified destination. The main aim of this method is to copy one array into another array.
This method basically copies a given array from all the specified sources of an array. In this way, you can easily merge two sorted arrays.
The certain number of elements that needs to be copied will be equal to its length argument.
Parameters to consider:
- Source_array: It consider the name of a required source array
- Starting_pos_source: This is called as the position where a source array should be copied
- Destination_array: This is the name of a required destination array
- Starting_pos_dest: In it, the position of a destination array that should be copied is considered
- Length: In it, the given length of the array is considered which needs to be copied. If it is not provided, you can copy a given array till its end.
Example;
To merge the given two arrays, we will find the given length of both of them. We can store array 1s length with that of the length of the array 2 in a variable. After this, we will create the new array to store the required sum of its length. Now, we can copy each element with the help of the arraycopy() method.
Java Stream API
If you have already installed the java 8 in the system, this would be an excellent feature for merging two sorted arrays. The API stream will offer so many methods that are useful for you to merge the two sorted arrays in java.
This API will be present in the form of java.util.stream java package. This also makes for the collection of certain packages which you can choose as per your convenience.
Using a java stream will help you work with the collection in java with the help of the two merge sorted arrays.
Using java collection
This is touted as another anticipated method to find merge sorted arrays. We know for the fact that the java collection is defined as the group of certain items with a single unit.
Their collection framework in any case will contain certain types of classes or interfaces in order to group so many different objects in a way that will make them into a single unit or the entire collection.
So, in this case we can say that we can easily merge two arrays with the help of a single array.
Guava library in java
The much popular guava library in java basically contains the concat() method which is quite useful to merge two arrays in order to return the concatenated content of the given two arrays.
The main parameters that needs to be considered in the case of guava library are:
- First -here the first element will be considered as the concatenate
- Second: here the second element would also be considered as concatenate
- Third: this will be the component type of a revered array
Wrapping Up
Array related questions are quite commonly asked in the coding interviews of all tech giants.
From reversing an array to find the second largest number in an array to subarray related problems, you would be asked several questions about various array concepts.
Learn about merging two sorted arrays with this tutorial and equip your knowledge bank!
