LeetCode - Excel Sheet Column Title

最新推荐文章于 2022-06-04 01:36:52 发布

转载最新推荐文章于 2022-06-04 01:36:52 发布 · 50 阅读

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原文链接：http://www.cnblogs.com/zhuli19901106/p/4244725.html

本文介绍了一种将正整数转换为Excel表格中对应列标题的方法。例如，1对应A，26对应Z，27对应AA等。通过递减和除基操作实现了O(log n)的时间复杂度。

Excel Sheet Column Title

2015.1.23 17:20

Given a positive integer, return its corresponding column title as appear in an Excel sheet.

For example:

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

Solution:

　　The code below is self-explanatory. It is a piecewise function.

　　Total time is O(log(n)), only in that the logarithm base here is 26.

Accepted code:

 1 // 1CE, 4WA, 1AC, so careless
 2 class Solution {
 3 public:
 4     string convertToTitle(int n) {
 5         long long int n1 = n;
 6         long long int base = 26;
 7         int len = 1;
 8         
 9         --n1;
10         while (n1 >= base) {
11             n1 -= base;
12             base *= 26;
13             ++len;
14         }
15         
16         string s;
17         
18         base /= 26;
19         while (base > 0) {
20             s.push_back(n1 / base + 'A');
21             n1 %= base;
22             base /= 26;
23         }
24         
25         return s;
26     }
27 };

转载于:https://www.cnblogs.com/zhuli19901106/p/4244725.html