LeetCode 744. Find Smallest Letter Greater Than Target (时间复杂度O（n）)

题目

太简单了，直接上代码：

class Solution {public:    char nextGreatestLetter(vector<char>& letters, char target) {        int n = letters.size();        int a[26] = {0};        for(int i = 0;i < n; ++i){            a[letters[i]-'a']++;        }        for(int i = (target-'a'+1)%26; ; i++,i%=26){            if(a[i] > 0) return (char)(i + 'a');        }    }};