How to Check if Array Contains a Value?

In this example, we will check if array contains a value or not.

1. JAVA

Using Linear Search

public class CheckIfArrayContainsANumber {
 
    public static void main(String[] args) {
        int unSortedArray[] = {13, 1, 8, 4, 9, 20, 44, 7, 3};
        System.out.println(checkNumber(unSortedArray, 3));
    }
 
    private static boolean checkNumber(int[] arr, int num) {
        for (int i = 0; i <= arr.length - 1; i++) {
            if (arr[i] == num) {
                return true;
            }
        }
        return false;
    }
}

Using Binary Search (if array is sorted)

public class CheckIfArrayContainsANumber {
 
    public static void main(String[] args) {
		int sortedArray[] = { 1, 2, 3, 4, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 };
		System.out.println(checkNumber(sortedArray, 0, sortedArray.length - 1, 15));
    }
 
	private static boolean checkNumber(int[] arr, int first, int last, int num) {
		for (int i = first; i <= last; i++) {
			int mid = (first + last) / 2;
			if (arr[i] == num) {
				return true;
			} else if (arr[i] < arr[mid]) {
				checkNumber(arr, first, mid - 1, num);
			} else if (arr[i] > arr[mid]) {
				checkNumber(arr, mid + 1, last, num);
			}
		}

		return false;
	}
}

Complete Java Solutions can be found here: Github Link

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