LeetCode Excel Sheet Column Number 171

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

public int titleToNumber(String s) {
	int col = 0;
	char[] chars = s.toCharArray();
	int i = 0;
	while (i < chars.length) {
		int charInt = chars[chars.length - 1 - i] - 64;
		col += Math.pow(26, i) * charInt;
		i++;
	}
	return col;
}