Leetcode 744. Find Smallest Letter Greater Than Target

744. Find Smallest Letter Greater Than Target

難易度

Easy

アプローチ

二分探索

class Solution {
    public char nextGreatestLetter(char[] letters, char target) {
        int letters_length = letters.length;
        int low = 0;
        int high = letters_length - 1;

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