旋转数组的最小数字（剑指Offer)

public static int minNumberInRotateArray(int[] array) {
int len = array.length;
if (len == 0) return 0;
else if (array[0] <= array[len - 1]) return array[0];
else if (array[len - 1] < array[len - 2]) return array[len - 1];
int beg = 0;
int end = array.length - 1;
//有旋转且不是最后一个 之所以把最后一个的判断放在上面是为了节约时间
while (beg <= end) {
int mid = (beg + end) / 2;
if (mid == 0) beg = mid + 1;
else if (array[mid] < array[mid - 1]) return array[mid];
else if (array[mid] >= array[0]) beg = mid + 1;
else if (array[mid] <= array[len - 1]) end = mid - 1;
}
return -1;
}