SearchInRotatedSortedArray.java

/**
 * Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand.
 * (i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2).
 * You are given nums target value to search. If found in the array return its index, otherwise return -1.
 * You may assume no duplicate exists in the array.
 * <p>
 * Accepted.
 */
public class SearchInRotatedSortedArray {

    public int search(int[] nums, int target) {
        if (nums == null || nums.length == 0) {
            return -1;
        }

        int l = 0, r = nums.length - 1;
        while (l <= r) {
            int m = (l + r) / 2;
            if (nums[m] == target) {
                return m;
            }
            if (nums[m] >= nums[l]) {
                if (nums[l] <= target && target < nums[m]) {
                    r = m - 1;
                } else {
                    l = m + 1;
                }
            } else {
                if (nums[m] < target && target <= nums[r]) {
                    l = m + 1;
                } else {
                    r = m - 1;
                }
            }
        }
        return -1;
    }

}