MadhavArray.java

public class MadhavArray {
	
//	A Madhav array has the following property.
//	a[0] = a[1] + a[2] = a[3] + a[4] + a[5] = a[6] + a[7] + a[8] + a[9] = ...
//	The length of a Madhav array must be n*(n+1)/2 for some n.
//	Write a method named isMadhavArray that returns 1 if its array argument is a Madhav array,
//	otherwise it returns 0. If you are programming in Java or C# the function signature is
//	int isMadhavArray(int[] a)
//
//	Examples
//	 -----------------------------------|-------|---------------------------------------------------
//	| if a is                           | return| reason                                            |
//	|-----------------------------------|-------|---------------------------------------------------|
//	| {2,1,1}                           | 1     | 2 = 1 + 1                                         |
//	|-----------------------------------|-------|---------------------------------------------------|
//	| {2,1,1,4,-1,-1}                   | 1     | 2 = 1 + 1, 2 = 4 + -1 + -1                        |
//	|-----------------------------------|-------|---------------------------------------------------|
//	| {6,2,4,2,2,2,1,5,0,0}             | 1     | 6 = 2 + 4, 6 = 2 + 2 + 2, 6 = 1 + 5 + 0 + 0       |
//	|-----------------------------------|-------|---------------------------------------------------|
//	| {18,9,10,6,6,6}                   | 0     | 18 != 9 + 10                                      |
//	|-----------------------------------|-------|---------------------------------------------------|
//	| {-6,-3,-3,8,-5,-4}                | 0     | -6 != 8 + -5 + -4                                 |
//	|-----------------------------------|-------|---------------------------------------------------|
//	| {0,0,0,0,0,0,0,0,0,0,1,1,1,-2,-1} | 1     | 0 = 0+0, 0 = 0+0+0, 0 = 0+0+0+0, 0 = 1+1+1+-2+-1  |
//	|-----------------------------------|-------|---------------------------------------------------|
//	| {3,1,2,3,0}                       | 0     | The length of the array is 5, but 5 != n*(n+1)/2  |
//	 -----------------------------------|-------|---------------------------------------------------
	
	
	static int isMadhavArray(int [] a) {
		
		if (a.length < 3) return 0;
		
		int isValidLength = 0;
		
		for (int i=1;i<=a.length;i++) {
			if (a.length == i*(i+1)/2) {
				isValidLength = 1;
			}
		}
		
		if (isValidLength == 0) {
			return 0;
		}
		
		int sumCheck = a[0];
		int sum = 0;
		int increment = 2;
		int indexCheck = 2;
		
		for (int i=1;i<a.length;i++) {
			if (i <= indexCheck){
				sum += a[i];
			}else {
				if (sumCheck != sum) {
					return 0;
				}else {
					sum = 0;
					increment = increment + 1;
					indexCheck = increment + i - 1;
					sum += a[i];
				}
			}
		}
		
		
		return sumCheck == sum ? 1 : 0;
	}
	
	
	static void madhavArrayTest() {
		System.out.println(isMadhavArray(new int[]{2,1,1}));
		System.out.println(isMadhavArray(new int[]{2,1,1,4,-1,-1}));
		System.out.println(isMadhavArray(new int[]{6,2,4,2,2,2,1,5,0,0} ));
		System.out.println(isMadhavArray(new int[]{18,9,10,6,6,6}));
		System.out.println(isMadhavArray(new int[]{-6,-3,-3,8,-5,-4}));
		System.out.println(isMadhavArray(new int[]{0,0,0,0,0,0,0,0,0,0,1,1,1,-2,-1}));
		System.out.println(isMadhavArray(new int[]{18,9,10,6,6,6}));
	}
	
	
	public static void main(String[] args) {
		madhavArrayTest();
	}

}