744.find-smallest-letter-greater-than-target.java

/*
 * @lc app=leetcode id=744 lang=java
 *
 * [744] Find Smallest Letter Greater Than Target
 */

// @lc code=start
class Solution {
    public char nextGreatestLetter(char[] letters, char target) {
        int low = 0;
        int high = letters.length - 1;

        while (low < high) {
            int mid = low + (high - low) / 2;
            if (letters[mid] <= target) {
                low = mid + 1;
            } else {
                high = mid;
            }
        }

        if (letters[low] <= target) {
            return letters[0];
        }

        return letters[low];
    }
}
// @lc code=end