challenge ctci-array-left-rotation

.gitignore

@@ -1,3 +1,4 @@
 node_modules
 build
-.idea
+.idea
+.DS_STORE

src/ctci-array-left-rotation/ctci-array-left-rotation.spec.ts

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+import {describe, it} from "node:test";
+import assert = require("node:assert");
+import {rotLeft} from "./ctci-array-left-rotation";
+
+describe("Ctci Array Left Rotation", () => {
+    describe("rotLeft", () => {
+        it("an empty array return itself ", () => {
+            assert.deepStrictEqual(rotLeft([], 100), [])
+            assert.deepStrictEqual(rotLeft([], 1), [])
+            assert.deepStrictEqual(rotLeft([], 0), [])
+        })
+
+        it("rotate an array of X position should return the array rotated left by X position", () => {
+            assert.deepStrictEqual(rotLeft([1, 2, 3, 4, 5], 4), [5, 1, 2, 3, 4]);
+        })
+    });
+})

src/ctci-array-left-rotation/ctci-array-left-rotation.ts

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+export function rotLeft(a: Array<number>, d: number): Array<number> {
+    if(a.length === 0) {
+        return [];
+    }
+
+    if(a.length == d) {
+        return a.reverse();
+    }
+
+    const firstElements = a.slice(0, d)
+    a.splice(0, d);
+    a = a.concat(firstElements);
+
+    return a;
+}