class Utility {

	static void print(int[] array) {
		for(int elm : array) {
			System.out.print(elm + " ");
		}
	}

	static int search(String[] array, String key) {
		int count = 0;
		for(String elm : array) {
			if (elm.equals(key)) {
				count++;	
			}
		}
		return count;
	}
			
	static int[] sum(int[] arr1, int[] arr2) {
		if (arr1.length != arr2.length) {
			return null;
		}

		int[] arr3 = new int[arr1.length];

		for(int i = 0; i < arr1.length; i++) {
			arr3[i] = arr1[i] + arr2[i];
		}

		return arr3;	
	} 

	static int[] getDiagonal(int[][] matrix) {
		int len = matrix.length;
		for(int[] row : matrix) {
			if (row.length != len) {
				return null;
			}
		}

		int[] diagonal = new int[len];
		for(int i = 0; i < len; i++) {
			diagonal[i] = matrix[i][i];
		}

		return diagonal;
	}
}