题目

Related to question Excel Sheet Column Title
Given a column title as appear in an Excel sheet, return its corresponding column number.
For example:

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

解题思路

该题目可以理解为26进制转换为10进制
从左到右遍历字符串，将每个字符转换成对应的进制，累加进总数，每次累加前总数先乘以进制26

代码

TitleToNumber.go

package _171_Excel_Sheet_Column_Number

func toNumber(tmp byte) int {
    return int(tmp - byte('A')) + 1
}
func TitleToNumber(s string) int {
    var ret int

    len1 := len(s)
    for i := 0; i < len1; i++ {
        tmp := s[i]
        tmpNum := toNumber(tmp)
        ret = ret * 26 + tmpNum
    }

    return ret
}

测试

TitleToNumber_test.go

package _171_Excel_Sheet_Column_Number

import "testing"

func TestTitleToNumber(t *testing.T) {
    var tests = []struct{
        input string
        output int
    } {
        {"AB", 28},
        {"A", 1},
    }

    for _, test := range tests {
        ret := TitleToNumber(test.input)

        if ret == test.output {
            t.Logf("pass")
        } else {
            t.Errorf("fail, want %+v, get %+v", test.output, ret)
        }
    }
}