Now you shift each digit down i.e. A' = 0, and Z' = 25.
Then 52 = AZ = (A' + 1) * 26 + (Z' + 1) * 1.
So now you need to find A' and Z'. Z' = (52 - 1) % 26 = 25, which is (n-1)%26 in the code above.
Now you need to get A' + 1 from 26 * (A' + 1) + (Z' + 1)
If you simply do n/=26, Z' + 1 will give additional 1. So you will get n = 2 instead of n = 1.
To avoid this you do n = (n-1)/26
public class Solution {
public String convertToTitle(int n) {
String res = "";
while(n != 0) {
char ch = (char)((n-1)%26 + 'A');
n = (n-1)/26;
res = ch + res;
}
return res;
}
}
Shawngbk
commented
7 years ago
Now you shift each digit down i.e. A' = 0, and Z' = 25. Then 52 = AZ = (A' + 1) * 26 + (Z' + 1) * 1.
So now you need to find A' and Z'. Z' = (52 - 1) % 26 = 25, which is (n-1)%26 in the code above. Now you need to get A' + 1 from 26 * (A' + 1) + (Z' + 1) If you simply do n/=26, Z' + 1 will give additional 1. So you will get n = 2 instead of n = 1. To avoid this you do n = (n-1)/26
public class Solution { public String convertToTitle(int n) { String res = ""; while(n != 0) { char ch = (char)((n-1)%26 + 'A'); n = (n-1)/26; res = ch + res; } return res; } }