pb 15

Author: EISAWESOME

README.md

@@ -217,4 +217,16 @@ The area of a circle is defined as `πr²`. Estimate `π` to 3 decimal places us
 Hint: The basic equation of a circle is `x² + y² = r²`.
 
 ### Solution
-[Python](pb14/answer.py) (19:37)
+[Python](pb14/answer.py) (19:37)
+
+
+---
+
+## 15
+> This problem was asked by Dropbox.
+
+Spreadsheets often use this alphabetical encoding for its columns: "A", "B", "C", ..., "AA", "AB", ..., "ZZ", "AAA", "AAB", ....
+Given a column number, return its alphabetical column id. For example, given 1, return "A". Given 27, return "AA".
+
+### Solution
+[JS](pb15/answer.js) (9:18)

pb15/Problem.md

@@ -0,0 +1,4 @@
+> This problem was asked by Dropbox.
+
+Spreadsheets often use this alphabetical encoding for its columns: "A", "B", "C", ..., "AA", "AB", ..., "ZZ", "AAA", "AAB", ....
+Given a column number, return its alphabetical column id. For example, given 1, return "A". Given 27, return "AA".

pb15/answer.js

@@ -0,0 +1,14 @@
+
+let alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+
+
+const getAlphaColId = (numId) => {    
+
+    let b26 = numId.toString(26);
+
+    let split = b26.split("");
+
+    return split.map(id => alphabet.charAt(id - 1)).join("");
+};
+
+console.log(getAlphaColId(27));