【题目】

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

【分析】

Because any_pos_int mod 26 should return a number in the interval [0, 25], but what we want is a number in the interval [1, 26]. Thus we have to shift the digit leftward by 1 which means--n.

【代码】

/**********************************   日期：2015-01-29*   作者：SJF0115*   题目: 168.Excel Sheet Column Title*   网址：https://oj.leetcode.com/problems/excel-sheet-column-title/*   结果：AC*   来源：LeetCode*   博客：**********************************/#include 
    
     #include 
     
      #include 
      
       using namespace std;class Solution {public:    string convertToTitle(int n) {        if(n <= 0){            return "";        }//if        vector
       
         vec;        --n;        // 除26取余倒排序        while(n >= 0){            vec.push_back(n % 26);            n /= 26;            --n;        }//        // 转换        string result;        int len = vec.size();        for(int i = 0;i < len;++i){            result.insert(result.begin(),vec[i]+'A');        }//for        return result;    }};int main(){    Solution solution;    for(int i = 500;i < 800;++i){        string result = solution.convertToTitle(i);        // 输出        cout<
        
         <<" ";    }    cout<
        
       
      
     
    

【代码二】

class Solution {public:    string convertToTitle(int n) {        if(n <= 0){            return "";        }//if        string result;        // 除26取余倒排序        while(n > 0){            n --;            result.insert(result.begin(),static_cast
    
     (n % 26 + 'A'));            n /= 26;        }//        return result;    }};