LeetCode – Excel Sheet Column Title (Java)

Problem

Given a positive integer, return its corresponding column title as appear in an Excel sheet. For example:

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

Java Solution

This problem is the reverse version of Excel Sheet Column Number.

The key is n--. The minimum in 26-bit number is mapped to 1, not 0.

public String convertToTitle(int n) {
    if(n <= 0){
        throw new IllegalArgumentException("Input is not valid!");
    }
 
    StringBuilder sb = new StringBuilder();
 
    while(n > 0){
        n--;
        char ch = (char) (n % 26 + 'A');
        n /= 26;
        sb.append(ch);
    }
 
    sb.reverse();
    return sb.toString();
}

If you want someone to read your code, please put the code inside <pre><code> and </code></pre> tags. For example:

<pre><code> 
String foo = "bar";
</code></pre>

Bhuvnesh Jangid

static String ColToString(int col) {
int rem=col%26;
if(rem==0) {
col–;
rem=26;
}
String s=””;
if(col>26){
col/=26;
s=ColToString(col)+String.valueOf((char)(rem+64));
}
else {
s+=String.valueOf((char)(rem+64));
}
return s;

}
Srinath Shah

No need for anything. add char to string in java 8
Srinath Shah

Dont need the toString perhaps?
Ankit

Good solution.Only just correct
s=String.valueOf((char)(n%26+’A’))+s;
Arjun Dubashi

You use a string builder because string concantenation operates in O(N^2) time
m00dy

Noob
Anna Kulik

There is no need to use a StringBuilder.
string s = ""; while(n>0) { n--; s = ((char)(n%26 +'A')).ToString() + s; n/=26; } return s;
Leetcode accepted this.
Thank you for the simple solution!

LeetCode – Excel Sheet Column Title (Java)

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