Given a list of sorted characters letters
containing only lowercase letters, and given a target letter target
, find the smallest element in the list that is larger than the given target.
Letters also wrap around. For example, if the target is target = ‘z‘
and letters = [‘a‘, ‘b‘]
, the answer is ‘a‘
.
Examples:
Input: letters = ["c", "f", "j"] target = "a" Output: "c" Input: letters = ["c", "f", "j"] target = "c" Output: "f" Input: letters = ["c", "f", "j"] target = "d" Output: "f" Input: letters = ["c", "f", "j"] target = "g" Output: "j" Input: letters = ["c", "f", "j"] target = "j" Output: "c" Input: letters = ["c", "f", "j"] target = "k" Output: "c"
Note:
letters
has a length in range[2, 10000]
.letters
consists of lowercase letters, and contains at least 2 unique letters.target
is a lowercase letter.
二分查找,找到大于给定目标的列表中最小的元素。
C++(19ms):
1 class Solution { 2 public: 3 char nextGreatestLetter(vector<char>& letters, char target) { 4 int left = 0 ; 5 int right = letters.size() - 1 ; 6 while(left < right){ 7 int mid = (left+right)>>1 ; 8 if (target < letters[mid]) 9 right = mid ; 10 else 11 left = mid + 1 ; 12 } 13 return target < letters[left] ? letters[left] : letters[0] ; 14 } 15 };
时间: 2024-11-09 14:13:05