Smallest Chatacter | tech::interview

Smallest Chatacter | tech::interview
Given a sorted character array and a character, return the smallest character that is strictly larger than the search character.
If no such character exists, return the smallest character in the array.
For example:
Input: ['c', 'f', 'j', 'p', 'v'], 'a'
Output: 'c'
Input: ['c', 'f', 'j', 'p', 'v'], 'c'
Output: 'f'
Input: ['c', 'f', 'j', 'p', 'v'], 'z'
Output: 'c'
Input: ['c', 'c', 'k'], 'f'
Output: 'k'
Binary Search:

    public char smallest_character(String str, char c) {

        int l = 0, r = str.length() - 1;

        char ret = str.charAt(0);

        while(l <= r) {

            int m = l + (r-l) / 2;

            if(str.charAt(m) > c) {

                ret = str.charAt(m);

                r = m - 1;

            } else {

                l = m + 1;

            }

        }

        return ret;

    }

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