Convert integer to roman number

Author: edignot

README.md

@@ -7,7 +7,7 @@ Each problem directory includes:
 
 There might still be some personal comments added for my learning purposes. 
 
-## Algorithms by Topic:
+## Algorithms:
 
 - **Math**
     * Fibonacci Sequence
@@ -37,6 +37,14 @@ There might still be some personal comments added for my learning purposes.
 [`Solution`](https://github.com/edignot/algorithm-data-structure-practice/blob/master/src/sorting/sorting.js) 
 [`Test file`](https://github.com/edignot/algorithm-data-structure-practice/blob/master/src/sorting/sorting.test.js)
 
+- **LeetCode**
+    * Valid Parentheses
+[`Solution`](https://github.com/edignot/algorithm-data-structure-practice/blob/master/src/valid-parentheses/valid-parentheses.js) 
+[`Test file`](https://github.com/edignot/algorithm-data-structure-practice/blob/master/src/valid-parentheses/valid-parentheses.test.js)
+    * Integer to Roman
+[`Solution`](https://github.com/edignot/algorithm-data-structure-practice/blob/master/src/integer-to-roman/integer-to-roman.js) 
+[`Test file`](https://github.com/edignot/algorithm-data-structure-practice/blob/master/src/integer-to-roman/integer-to-roman.test.js)
+
 - **All**
     * Snail
 [`Solution`](https://github.com/edignot/algorithm-data-structure-practice/blob/master/src/snail/snail.js) 
@@ -47,9 +55,7 @@ There might still be some personal comments added for my learning purposes.
     * Tree relation
 [`Solution`](https://github.com/edignot/algorithm-data-structure-practice/blob/master/src/recursion-tree/recursion-tree.js) 
 [`Test file`](https://github.com/edignot/algorithm-data-structure-practice/blob/master/src/recursion-tree/recursion-tree.test.js)
-    * Valid Parentheses
-[`Solution`](https://github.com/edignot/algorithm-data-structure-practice/blob/master/src/valid-parentheses/valid-parentheses.js) 
-[`Test file`](https://github.com/edignot/algorithm-data-structure-practice/blob/master/src/valid-parentheses/valid-parentheses.test.js)
+
 
 ## Usage
 -   Clone this repo

src/integer-to-roman/integer-to-roman.js

@@ -0,0 +1,34 @@
+// Problem: Given an integer, convert it to a roman numeral
+// https://leetcode.com/problems/integer-to-roman/
+// Time complexity: O(n)
+
+const integerToRoman = (num) => {
+    const romans = {
+        M: 1000,
+        CM: 900,
+        D: 500,
+        CD: 400,
+        C: 100,
+        XC: 90,
+        L: 50,
+        XL: 40,
+        X: 10,
+        IX: 9,
+        V: 5,
+        IV: 4,
+        I: 1,
+    };
+    const romanNum = [];
+    for (const roman in romans) {
+        if (num >= romans[roman]) {
+            const amount = Math.floor(num / romans[roman]);
+            for (let i = 0; i < amount; i++) {
+                romanNum.push(roman);
+            }
+            num -= amount * romans[roman];
+        }
+    }
+    return romanNum.join("");
+};
+
+export default integerToRoman;

src/integer-to-roman/integer-to-roman.test.js

@@ -0,0 +1,13 @@
+import integerToRoman from "./integer-to-roman";
+
+describe("Integer to Roman number", () => {
+    test("Integer to Roman number", () => {
+        expect(integerToRoman(126)).toBe("CXXVI");
+    });
+    test("Integer to Roman number", () => {
+        expect(integerToRoman(234)).toBe("CCXXXIV");
+    });
+    test("Integer to Roman number", () => {
+        expect(integerToRoman(0)).toBe("");
+    });
+});