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
26進制運算,聯繫java中String類的的使用,atChar,length()等
java中的char類型,即'A'
public class Solution {
public int titleToNumber(String s) {
int l=s.length();
int v=0;
for(int i=0;i<l;i++)
v=v*26+(s.charAt(i)-'A'+1);
return v;
}
}