二分法
class Solution {
public int search(int[] nums, int target) {
int left = 0, right = nums.length - 1;
while (left <= right) {
int mid = (left + right) / 2;
if (nums[mid] == target) {
return mid;
}
if (nums[left] <= nums[mid]) {
// 左半部分有序
if (nums[left] <= target && target < nums[mid]) {
right = mid - 1;
} else {
left = mid + 1;
}
} else {
// 右半部分有序
if (nums[mid] < target && target <= nums[right]) {
left = mid + 1;
} else {
right = mid - 1;
}
}
}
return -1;
}
}