feat: exercises from chapter 7

Author: damianobacci

chapter-7/ex1.ts

@@ -0,0 +1,14 @@
+function arrayIntersection(arr1: number[], arr2: number[]): number[] {
+    let mappedArray = new Map<number, boolean>();
+    for (const num of arr1) {
+        mappedArray.set(num, true);
+    }
+    let intersection: number[] = [];
+
+    for (const num of arr2) {
+        if (mappedArray.has(num)) {
+            intersection.push(num);
+        }
+    }
+    return intersection;
+}

chapter-7/ex2.ts

@@ -0,0 +1,11 @@
+function findFirstDuplicate(array: string[]): string {
+    const hash = new Map<string, boolean>()
+
+    for (const str of array) {
+        if (hash.has(str)) {
+            return str
+        }
+        hash.set(str, true)
+    }
+    return 'No duplicates found'
+}