Li Kou daily question - day 43 -168. Name of Excel table column

2022.7.26 Did you brush the questions today ？

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subject ：

Give you an integer  columnNumber , Back to it in Excel The name of the corresponding column in the table .

for example ：

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

analysis ：

Given an integer , Turn it into a string , The rules are similar 26 Hexadecimal conversion .

Ideas ： about 10 Turn into the system n Binary problem , You can use the module of complementary sum to calculate . For example, in this question , Take the integer first every time 26 The mold , Get the lowest , Then use the mathematical formula to update the integer .

analysis ：

class Solution {
public:
    string convertToTitle(int columnNumber) {
        string ans;
        while (columnNumber > 0) {
            int a0 = (columnNumber - 1) % 26 + 1;
            ans += a0 - 1 + 'A';
            columnNumber = (columnNumber - a0) / 26;
        }
        reverse(ans.begin(), ans.end());
        return ans;
    }
};