Given a string columnTitle that represents the 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
...
Example 1:
Input: columnTitle = "A"
Output: 1
Example 2:
Input: columnTitle = "AB"
Output: 28
Example 3:
Input: columnTitle = "ZY"
Output: 701
Constraints:
1 <= columnTitle.length <= 7
columnTitle consists only of uppercase English letters.
columnTitle is in the range ["A", "FXSHRXW"].
Solution:
class Solution {
public int titleToNumber(String columnTitle) {
if(columnTitle==null) return -1;
int sum=0;
for(char c: columnTitle.toCharArray())
{
sum*=26;
sum+=c-'A'+1;
}
return sum;
}
}
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