171. Excel Sheet Column Number

problem

​​171. Excel Sheet Column Number​​

sum( (s[i]-'A'+1)*pow(26, i) )

code

class Solution {
public:
int titleToNumber(string s) {
int n=0;
int ans = 0;
while(n<s.size())
{
ans = ans*26 + (s[n] - 'A' + 1);
n++;
}
return ans;
}
};

 

 

1. ​​Leetcode_Excel Sheet Column Number​​;