README_EN.md

744. Find Smallest Letter Greater Than Target

中文文档

Description

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:

1. letters has a length in range [2, 10000].
2. letters consists of lowercase letters, and contains at least 2 unique letters.
3. target is a lowercase letter.

Solutions

Python3

class Solution:
    def nextGreatestLetter(self, letters: List[str], target: str) -> str:
        left, right = 0, len(letters)
        while left < right:
            mid = (left + right) >> 1
            if ord(letters[mid]) > ord(target):
                right = mid
            else:
                left = mid + 1
        return letters[left % len(letters)]

Java

class Solution {
    public char nextGreatestLetter(char[] letters, char target) {
        int left = 0, right = letters.length;
        while (left < right) {
            int mid = (left + right) >> 1;
            if (letters[mid] > target) {
                right = mid;
            } else {
                left = mid + 1;
            }
        }
        return letters[left % letters.length];
    }
}

TypeScript

function nextGreatestLetter(letters: string[], target: string): string {
    let left = 0,
        right = letters.length;
    let x = target.charCodeAt(0);
    while (left < right) {
        let mid = (left + right) >> 1;
        if (x < letters[mid].charCodeAt(0)) {
            right = mid;
        } else {
            left = mid + 1;
        }
    }
    return letters[left % letters.length];
}

C++

class Solution {
public:
    char nextGreatestLetter(vector<char>& letters, char target) {
        int left = 0, right = letters.size();
        while (left < right) {
            int mid = left + right >> 1;
            if (letters[mid] > target) {
                right = mid;
            } else {
                left = mid + 1;
            }
        }
        return letters[left % letters.size()];
    }
};

Go

func nextGreatestLetter(letters []byte, target byte) byte {
	left, right := 0, len(letters)
	for left < right {
		mid := (left + right) >> 1
		if letters[mid] > target {
			right = mid
		} else {
			left = mid + 1
		}
	}
	return letters[left%len(letters)]
}

...