171.Excel Sheet Column Number

Related toquestion Excel Sheet Column Title

Given a columntitle as appear in an Excel sheet, return its corresponding column number.

For example:

#pragma once
#include<queue>
#include<iostream>
using namespace std;

struct TreeNode {
	int val;
	TreeNode *left;
	TreeNode *right;
	TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};


int titleToNumber(string s) {
	char* p = (char*)s.c_str();
	int sum = 0;
	while (*p)
	{
		sum *= 26;
		sum += *p - 'A' + 1;
		p++;
	}
	return sum;
}

void main()
{
	cout << titleToNumber("AB") << endl;
	system("pause");

}