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.
public class Solution {
public char NextGreatestLetter(char[] letters, char target) {
if(target>=letters[letters.Length-1]){
return letters[0];
}
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;
}
}
return letters[high];
}
}Time Complexity: O(logn)
Space Complexity: O(1)
