[Hacker Rank] Interview Preparation Kit: Hash Tables: Ice Cream Parlor. Optimized solution ✅.

Author: Gonzalo Diaz

src/hackerrank/interview_preparation_kit/search/ctci_ice_cream_parlor_optimized.test.ts

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+import { describe, expect, it } from '@jest/globals';
+import { logger as console } from '../../../logger';
+
+import {
+  whatFlavors,
+  whatFlavorsCompute
+} from './ctci_ice_cream_parlor_optimized';
+import TEST_CASES from './ctci_ice_cream_parlor.testcases.json';
+import TEST_CASES_BORDER_CASES from './ctci_ice_cream_parlor.border_testcases.json';
+
+describe('ctci_ice_cream_parlor_optimized', () => {
+  it('whatFlavorsCompute test cases', () => {
+    expect.assertions(10);
+
+    TEST_CASES.forEach((testSet) => {
+      testSet?.tests.forEach((test) => {
+        const answer = whatFlavorsCompute(test.costs, test.money);
+
+        console.debug(
+          `${testSet.title} whatFlavorsCompute(${test.costs}, ${test.money}) solution found: ${answer}`
+        );
+
+        expect(answer).toStrictEqual(test.expected);
+        expect(whatFlavors(test.costs, test.money)).toBeUndefined();
+      });
+    });
+  });
+
+  it('whatFlavors border test cases', () => {
+    expect.assertions(2);
+
+    TEST_CASES_BORDER_CASES.forEach((testSet) => {
+      testSet?.tests.forEach((test) => {
+        expect(whatFlavorsCompute(test.costs, test.money)).toStrictEqual(
+          test.expected
+        );
+        expect(whatFlavors(test.costs, test.money)).toBeUndefined();
+      });
+    });
+  });
+
+  it('whatFlavors test caller function', () => {
+    expect.assertions(1);
+
+    const cost: number[] = [];
+    const money: number = 100;
+
+    expect(whatFlavors(cost, money)).toBeUndefined();
+  });
+});

src/hackerrank/interview_preparation_kit/search/ctci_ice_cream_parlor_optimized.ts

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+/**
+ * @link Problem definition [[docs/hackerrank/interview_preparation_kit/search/ctci-ice-cream-parlor.md]]
+ */
+
+export function whatFlavorsCompute(cost: number[], money: number): number[] {
+  let ans1;
+  let ans2;
+
+  const CACHE: Record<number, number> = {};
+
+  for (const price of cost) {
+    CACHE[price] = Number.isInteger(CACHE[price]) ? CACHE[price] + 1 : 1;
+  }
+
+  for (const i in cost) {
+    const v1 = cost[i];
+    const v2 = money - v1;
+
+    if (v1 != v2) {
+      if (CACHE?.[v1] && CACHE?.[v2]) {
+        ans1 = v1;
+        ans2 = v2;
+        break;
+      }
+    } else {
+      // count of the element must be greater than 1 if they are same
+      if (CACHE?.[v1] && CACHE[v1] > 1) {
+        ans1 = v1;
+        ans2 = v1;
+        break;
+      }
+    }
+  }
+
+  const result: Set<number> = new Set();
+  for (const i in cost) {
+    const x: number = parseInt(i);
+
+    if (cost[x] == ans1 || cost[x] == ans2) {
+      result.add(x + 1);
+    }
+  }
+
+  return Array.from(result);
+}
+
+export function whatFlavors(cost: number[], money: number): void {
+  console.log(whatFlavorsCompute(cost, money)?.join(' '));
+}
+
+export default { whatFlavorsCompute, whatFlavors };