leetcode_168题——Excel Sheet Column Title（数学问题）

Excel Sheet Column Title

Total Accepted: 25652 Total Submissions: 142582My Submissions

Question Solution

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 

Credits:
Special thanks to @ifanchu for adding this problem and creating all test cases.

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Math

这道题其实就是将10进制转化为26进制的计算，只是从1开始，而不是从零开始，所以有点搞人，开始的时候想了个笨办法，发现超时了

后来看了下别人的解法

#include<iostream>
#include<string>
#include<math.h>
using namespace std;
/*
string convertToTitle(int n) {
	string str1;
	int i=0;
	int a=n;
	while(1)
	{
		int pinf_i=pow(26.0,i);
		int pinf_ii=pow(26.0,i+1);
		int b;
		if(a<=pinf_ii)
		{b=a/pinf_i;str1.push_back(b+64);break;}

		if(a>pinf_ii)
		{
			if(a%pinf_ii==0)
			{
				str1.push_back(‘Z‘);
				a=a-26*pinf_i;
			}
			else
			{
				b=(a%pinf_ii)/pinf_i;
				str1.push_back(b+64);
				a=a-b*pinf_i;
			}
			i++;
		}
	}
	string str2;
	int N=str1.size();
	while(N--)
	{
		str2.push_back(str1.back());
		str1.pop_back();
	}
	return str2;
}
*/
string convertToTitle(int n)
{
	string str1;

	while(n!=0)
	{
		n--;
		str1.push_back(n%26+65);
		n/=26;
	}
	string str2;
	int N=str1.size();
	while(N--)
	{
		str2.push_back(str1.back());
		str1.pop_back();
	}
	return str2;
}

int main()
{
	cout<<convertToTitle(703)<<endl;
}