Problem:
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
Summary:
将二十六进制数字转为十进制。
Analysis:
class Solution {
public:
int titleToNumber(string s) {
int len = s.size();
int res = ;
for (int i = ; i < len; i++) {
res += (s[len - i - ] - 'A' + ) * pow(, i);
}
return res;
}
};