171. Excel 表列序号

English Version

题目描述

给你一个字符串 columnTitle ，表示 Excel 表格中的列名称。返回 该列名称对应的列序号 。

例如：

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

 

示例 1:

输入: columnTitle = "A"
输出: 1

示例 2:

输入: columnTitle = "AB"
输出: 28

示例 3:

输入: columnTitle = "ZY"
输出: 701

 

提示：

• 1 <= columnTitle.length <= 7
• columnTitle 仅由大写英文组成
• columnTitle 在范围 ["A", "FXSHRXW"] 内

解法

Python3

class Solution:
    def titleToNumber(self, columnTitle: str) -> int:
        res = 0
        for c in columnTitle:
            res = res * 26 + (ord(c) - ord('A') + 1)
        return res

Java

class Solution {
    public int titleToNumber(String columnTitle) {
        int res = 0;
        for (char c : columnTitle.toCharArray()) {
            res = res * 26 + (c - 'A' + 1);
        }
        return res;
    }
}

TypeScript

function titleToNumber(columnTitle: string): number {
    let res: number = 0;
    for (let char of columnTitle) {
        res = res * 26 + char.charCodeAt(0) - 64;
    }
    return res;
}

C++

class Solution {
public:
    int titleToNumber(string columnTitle) {
        int res = 0;
        for (char c : columnTitle) {
            res = res * 26 + (c - 'A' + 1);
        }
        return res;
    }
};

Go

func titleToNumber(columnTitle string) int {
	res := 0
	for _, c := range columnTitle {
		res = res*26 + int(c-'A'+1)
	}
	return res
}

...