Page 5

T: O(n)

S: O(1)

class Solution {
    public int titleToNumber(String s) {
        // System.out.println((int)('B' - 'A')+1);
        int n = s.length();
        int res = 0;
        for (int i = 0; i < n; i++) {
            res *= 26;
            res += (s.charAt(i) - 'A')+1;
        }
        return res;
    }
}


/*
Z -> 26
Y -> 25

ZY


26*26 + 25

 26*26 = 676
 676+25 = 701


like the cal number => 213 = 2*10*10 + 1*10 + 3
=> 2
=> 2*10 + 1
=> (2*10 + 1)*10 + 3 = 213

BCM

=> 

B*26*26 + C*26 + M


1. B
2. B*26 + C
3. (B*26 + C)*26 + M

*/