Check if Array Contains All Elements Of Some Given Range

Objective: Given an array of unsorted numbers, check if it contains all elements of some given range.

Examples:

int[] arrA = { 11, 17, 13, 19, 15, 16, 12, 14 };
Range : 12-15
Output: True

Approach:

Naive Approach: Sorting . Time Complexity – O(nlogn).

Better Approach: Time Complexity – O(n).

Find the range = y-x;
Do the linear scan of array.
Check if element falls within the range of x and y, (arrA[i]>=x && arrA[i]<=y)
If Yes then calculate z = arrA[i]-x;
Make the arrA[z] element as negative.
Once the linear scan is done, just check all the elements in arrA[] from 0 to range are negative, if yes them array contains all the numbers of the given range, return true, else false.
See the Picture below for better explanation

Complete Code:

	public class CheckArrayContainsAllElementsInGivenRange {

	public Boolean find(int[] arrA, int x, int y) {
	int range = y – x;
	for (int i = 0; i < arrA.length; i++) {
	if (arrA[i] >= x && arrA[i] <= y) {
	int z = arrA[i] – x;
	if (arrA[z] > 0) {
	arrA[z] = arrA[z] * –1;
	}
	}
	}
	// for(int i=0;i<arrA.length;i++){
	// System.out.print(" " + arrA[i]);
	// }
	for (int i = 0; i < range; i++) {
	if (arrA[i] > 0)
	return false;
	}
	return true;
	}

	public static void main(String[] args) throws java.lang.Exception {
	int[] arrA = { 11, 17, 13, 19, 15, 16, 12, 14 };
	int x = 12;
	int y = 15;
	CheckArrayContainsAllElementsInGivenRange i = new CheckArrayContainsAllElementsInGivenRange();
	System.out.println(i.find(arrA, x, y));
	}
	}

Output:

True