DataUtil { public static int binarySearch(int[] array, int key) { int left = 0; int right = array.length - 1; while (left <= right) { int mid = (left + right) / 2; if (array[mid] == key) { return mid; } else if (array[mid] < key) { left = mid + 1; } else { right = mid - 1; } } return -1; }  static int getMatrixHeavy(int[][] matrix, int m, int n); static int maxSequenceSum(int[] array); static int fibonacciRecursive(int n); static int fibonacci(int n); static int findMaxUnContinuousSum(int[] array); static void findContinuousSequenceMethod1(int n); static void findContinuousSequenceMethod2(int n); static void findContinuousSequenceMethod3(int n); static void findContinuousSequenceMethod4(int n); static void pickNum(int[] originArray, int n, int m, int[] selectArray, int startIndex, boolean inorder); static int binarySearch(int[] array, int key); static int findFirstEqual(int[] array, int key); static int findFirstEqualLarger(int[] array, int key); static int findFirstLarger(int[] array, int key); static int findLastEqual(int[] array, int key); static int findLastEqualSmaller(int[] array, int key); static List<Integer> shufflePump(List<Integer> origin); static List<Integer> shuffleSwap(List<Integer> origin); static int[] shuffleSwap(int[] origin); static String getAccurateDivide(int a, int b, int n); static Set<Integer> getPrimeNumInefficient(int range); static Set<Integer> getPrimeNumEfficient(int range); static int getIntervalDays(int year, int month, int day); static int pageHelper(int n, int m); static boolean isOdd(int num);  }
@Test public void binarySearch() { int n = 50; int[] array = new int[n]; for (int i = 0; i < array.length; i++) { if (i < 40) { array[i] = i; } else { array[i] = 40; } } int data = 40; logger.info("binarySearch, data is: {}, index is: {}", data, DataUtil.binarySearch(array, data)); logger.info("findFirstEqual, data is: {}, index is: {}", data, DataUtil.findFirstEqual(array, data)); logger.info("findLastEqualSmaller, data is: {}, index is: {}", data, DataUtil.findLastEqualSmaller(array, data)); }