二分查找

// 递归形式

public static int BinartSearch(int[] array, int low, int high, int target) {    if (low <= high) {        int mid = (low + high) / 2;        if (array[mid] == target) {            return mid;        } else if (array[mid] < target)            return BinartSearch(array, mid + 1, high, target);        else            return BinartSearch(array, low, mid - 1, target);    } else {        return -1;    }}

// 循环形式public static int BinartSearch(int[] array, int low, int high, int target) {    int mid;    while (low <= high) {        mid = (low + high) / 2;        if (array[mid] == target)            return mid;        else if (array[mid] < target)            low = mid + 1;        else high = mid - 1;    }    return -1;}