java简单算法（二分查找 冒泡排序 判断是否为素数)

public static int binarySearch(int[] arr, int data, int beginIndex, int endIndex) {
int midIndex = (beginIndex + endIndex) / 2;
if (data > arr[endIndex] || data < arr[beginIndex] || beginIndex > endIndex) {
return -1;
}
if (data > arr[midIndex]) {
return binarySearch(arr, data, midIndex + 1, endIndex);
} else if (data < arr[midIndex]) {
return binarySearch(arr, data, beginIndex, midIndex - 1);
} else {
return midIndex;
}
}

public static int binarySearch(int[] arr, int data) {
int beginIndex = 0;
int endIndex = arr.length - 1;
int midIndex = -1;
if (data > arr[endIndex] || data < arr[beginIndex] || beginIndex > endIndex) {
return -1;
}
while (beginIndex <= endIndex) {
midIndex = (beginIndex + endIndex) / 2;
if (data > arr[midIndex]) {
beginIndex = midIndex + 1;
} else if (data < arr[midIndex]) {
endIndex = midIndex - 1;
} else {
return midIndex;
}
}
return -1;
}

public static void bubbleSort(int[] arr) {
int temp = 0;
for (int i = 0; i < arr.length - 1; i++) {
for (int j = 0; j < arr.length - i - 1; j++) {
if (arr[j] > arr[j + 1]) {
temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
}
}
}
}

public static boolean isPrimeNumber(int num) {
for (int i = 2; i <= Math.sqrt(num); i++) {
if (num % i == 0) {
return false;
}
}
return true;
}