UpCount.java

public class UpCount {
	
//	Define the n-upcount of an array to be the number of times the partial sum goes from less than
//	or equal to n to greater than n during the calculation of the sum of elements of the array.
//	if you are programming in Java or C#, the function signature is int nUpCount(int[] a, int n)
//
//	For example, if n=5, the 5-upcount of the array {2,3,1,-6,8,-3,-1,2} is 3.
//	 ------|------|--------------|---------|---------------------------------
//	| i    | a[i] | partial sum  | upcount | comment                         |
//	|------|------|--------------|---------|---------------------------------|
//	| 0    | 2    | 2            |         |                                 |
//	|------|------|--------------|---------|---------------------------------|
//	| 1    | 3    | 5            |         |                                 |
//	|------|------|--------------|---------|---------------------------------|
//	| 2    | 1    | 6            | 1       | partial sum goes from 5 to 6    |
//	|------|------|--------------|---------|---------------------------------|
//	| 3    | -6   | 0            |         |                                 |
//	|------|------|--------------|---------|---------------------------------|
//	| 4    | 8    | 8            | 2       | partial sum goes from 0 to 8    |
//	|------|------|--------------|---------|---------------------------------|
//	| 5    | -3   | 5            |         |                                 |
//	|------|------|--------------|---------|---------------------------------|
//	| 6    | -1   | 4            |         |                                 |
//	|------|------|--------------|---------|---------------------------------|
//	| 7    | 2    | 6            | 3       | partial sum goes from 4 to 6    |
//	 ------|------|--------------|---------|---------------------------------
	
	static int nUpCount(int [] a,int n) {
		int upcount = 0;
		int prevSum = 0;
		int sum = 0;
		
		for (int i=0;i<a.length;i++) {
			prevSum = sum;
			sum += a[i];
			
			if (prevSum <= n && sum > n) {
				upcount++;
			}
		}
		
		return upcount;
	}
	
	static void poeArrayTest() {
		System.out.println(nUpCount(new int[] {2,3,1,-6,8,-3,-1,2},5));
	}
	
	
	public static void main(String[] args) {
		poeArrayTest();
	}

}