Equal Sum Partition

For a given array, we need to check whether an array can be divided into two equal parts. The array i.e{1,5,11,5} can be divide into
two parts:-- {1,5,5},{11}
Thus the O/p= TRUE

Approach:-- At first, we need to see whether the sum of the array is divisble by 2. If yes then only we will continue otherwise there is 
no chance of equal partition. Eg:- 22 can be divided into 11 and 11 but  21 will be 10 and 11(i.e unequal).

Now if the sum is even , does not mean equal partition must occur.
For example, {9,9,3,2,3} can be divided with Equal Sum because,
Sum=9+9+3+2+3=26

So, if we want equal partition, we need to check whether an array with subset sum=intial sum(i.e 26 in this case)/2 =13 exist or not.
We don't have any such subset in {9,9,3,2,3}.
Thus the O/p= FALSE

Code:--


import java.util.*;
import java.lang.*;
import java.io.*;


class Codechef
{
	public static void main (String[] args) throws java.lang.Exception
	{
		// your code goes here
			Scanner sc=new Scanner(System.in);
	int n=sc.nextInt();
	int a[]=new int[n];
	int sum=0;
	for(int i=0;i<n;i++) {
		a[i]=sc.nextInt();
		sum+=a[i];}
	
	if(isEqual_Sum_PartitonPossible(a,sum))
		System.out.println(true);
	else
		System.out.println(false);
	}
static boolean isEqual_Sum_PartitonPossible(int a[],int sum)
{
	if(sum%2!=0)
		return false;
	else
		return (Subset_Sum_possible_or_Not(a,sum/2));
}
//Now if the sum is even , does not mean equal partition must occur.
static boolean Subset_Sum_possible_or_Not(int a[],int sum)
{
	boolean dp[][]=new boolean[a.length+1][sum+1];
	
	for(int i=0;i<=a.length;i++)
	{
		for(int j=0;j<=sum;j++)
		{
			if(i==0)
				dp[i][j]=false;
			else if(j==0)
				dp[i][j]=true;
			else if(a[i-1]<=j)
				dp[i][j]=dp[i-1][j-a[i-1]]||dp[i-1][j];
			else
				dp[i][j]=dp[i-1][j];
		}
	}
	return dp[a.length][sum];
}
}