[LeetCode] Excel Sheet Column Number

Related to question Excel Sheet Column Title

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

For example:

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

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

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---

  比较简单的题目。

#include <iostream>
#include <string>
using namespace std;


class Solution {
public:
    int titleToNumber(string s) {
        int n = s.length();
        if(n<1) return 0;
        int seed =1;
        int sum = 0;
        for(int i = n-1;i>=0;i--){
            sum += (s[i]-'A'+1)*seed;
            seed*=26;
        }
        return sum;
    }
};

int main()
{
    string s="AAA";
    Solution sol;
    cout<<sol.titleToNumber(s)<<endl;
    return 0;
}