Poison

33. Search in Rotated Sorted Array

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class Solution {
    public int search(int[] nums, int target) {
        int left = 0, right = nums.length - 1;
        while (left <= right) { // 注意此处是小于等于
            int mid = (left + right) >>> 1;
            if (nums[mid] == target) {
                return mid;
            }

            if (nums[left] <= nums[mid]) {
                // 左半数组递增
                if (nums[left] <= target && target < nums[mid]) {
                    right = mid - 1;
                } else {
                    left = mid + 1;
                }
            } else {
                // 右半数组递增
                if (nums[mid] < target && target <= nums[right]) {
                    left = mid + 1;
                } else {
                    right = mid - 1;
                }
            }
        }

        return -1;
    }
}
Reference

33. Search in Rotated Sorted Array