168. Excel 表列名称

English Version

题目描述

给定一个正整数，返回它在 Excel 表中相对应的列名称。

例如，

    1 -> A
    2 -> B
    3 -> C
    ...
    26 -> Z
    27 -> AA
    28 -> AB 
    ...

示例 1:

输入: 1
输出: "A"

示例 2:

输入: 28
输出: "AB"

示例 3:

输入: 701
输出: "ZY"

解法

Python3

class Solution:
    def convertToTitle(self, columnNumber: int) -> str:
        res = []
        while columnNumber:
            columnNumber -= 1
            res.append(chr(ord('A') + columnNumber % 26))
            columnNumber //= 26
        return ''.join(res[::-1])

Java

class Solution {
    public String convertToTitle(int columnNumber) {
        StringBuilder res = new StringBuilder();
        while (columnNumber != 0) {
            --columnNumber;
            res.append((char) ('A' + columnNumber % 26));
            columnNumber /= 26;
        }
        return res.reverse().toString();
    }
}

TypeScript

function convertToTitle(columnNumber: number): string {
    let res: string[] = [];
    while (columnNumber > 0) {
        --columnNumber;
        let num: number = columnNumber % 26;
        res.unshift(String.fromCharCode(num + 65));
        columnNumber = Math.floor(columnNumber / 26);
    }
    return res.join('');
};

C#

public class Solution {
    public string ConvertToTitle(int columnNumber) {
        StringBuilder res = new StringBuilder();
        while (columnNumber != 0) {
            --columnNumber;
            res.Append((char) ('A' + columnNumber % 26));
            columnNumber /= 26;
        }
        return new string(res.ToString().Reverse().ToArray());
    }
}

...