题解 | #二分查找-II#

/***
*注意数字边界值检测。注意high和low的数值变化
*/
public static int search(int[] nums, int target) {
// write code here
if (nums.length == 0) {
return -1;
}
int high = nums.length - 1;
int low = 0;
int mid = (high + low) / 2;
if (nums[low] == target) {
return low;
}
if (nums[high] == target) {
while (nums[high] == nums[high - 1]) {
high = high - 1;
}
return high;
}
while (low < high) {
if (target < nums[mid]) {
high = mid - 1;
} else if (target > nums[mid]) {
low = mid + 1;
} else {
while (low < mid) {
if (nums[mid] != nums[mid - 1]) {
return mid;
}
mid = mid - 1;
}
return mid;
}
mid = (high + low) / 2;
}
return -1;
}