[REFACTOR] [Hacker Rank] Interview Preparation Kit: Dictionaries and Hashmaps: Frequency Queries. First solution and optimized solution splitted in two separated solutions.

Author: Gonzalo Diaz

src/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/frequency_queries.test.js

@@ -0,0 +1,46 @@
+/**
+ * @link Problem definition [[docs/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/frequency-queries.md]]
+ */
+
+export function freqQuery(queries) {
+  const result = [];
+  const dataMap = {};
+
+  const __INITIAL__ = 0;
+  const __INSERT__ = 1;
+  const __DELETE__ = 2;
+  const __SELECT__ = 3;
+
+  const __NOT_FOUND__ = 0;
+  const __FOUND__ = 1;
+
+  queries.forEach((query) => {
+    const [operation, data] = query;
+
+    const current = dataMap?.[data] ?? __INITIAL__;
+
+    switch (operation) {
+      case __INSERT__:
+        dataMap[data] = current + 1;
+        break;
+      case __DELETE__:
+        dataMap[data] = Math.max(0, current - 1);
+        break;
+      case __SELECT__: {
+        const uniqueDatavalues = new Set(Object.values(dataMap));
+        if (uniqueDatavalues.has(data)) {
+          result.push(__FOUND__);
+        } else {
+          result.push(__NOT_FOUND__);
+        }
+        break;
+      }
+      default:
+        throw new Error('Invalid operation');
+    }
+  });
+
+  return result;
+}
+
+export default { freqQuery };

src/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/frequency_queries_bruteforce.js

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+import { describe, expect, it } from '@jest/globals';
+import { logger as console } from '../../../logger.js';
+
+import { freqQuery } from './frequency_queries_bruteforce.js';
+import SMALL_TEST_CASES from './frequency_queries_testcases.json';
+
+describe('frequency_queries', () => {
+  it('freqQuery test cases', () => {
+    expect.assertions(4);
+
+    SMALL_TEST_CASES.forEach((value) => {
+      const answer = freqQuery(value.input);
+
+      console.debug(`freqQuery(${value.input}) solution found: ${answer}`);
+
+      expect(answer).toStrictEqual(value.expected);
+    });
+  });
+
+  it('freqQuery border case', () => {
+    expect.assertions(1);
+
+    expect(() => {
+      freqQuery([[4, 1]]);
+    }).toThrow('Invalid operation');
+  });
+});

src/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/frequency_queries_bruteforce.test.js

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+import { describe, expect, it } from '@jest/globals';
+import { logger as console } from '../../../logger.js';
+
+import { freqQuery } from './frequency_queries_optimized.js';
+import TEST_CASES from './frequency_queries_testcases.json';
+
+describe('frequency_queries', () => {
+  it('freqQuery test cases', () => {
+    expect.assertions(4);
+
+    TEST_CASES.forEach((value) => {
+      const answer = freqQuery(value.input);
+
+      console.debug(`freqQuery(${value.input}) solution found: ${answer}`);
+
+      expect(answer).toStrictEqual(value.expected);
+    });
+  });
+
+  it('freqQuery border case', () => {
+    expect.assertions(1);
+
+    expect(() => {
+      freqQuery([[4, 1]]);
+    }).toThrow('Invalid operation');
+  });
+});

src/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/frequency_queries.js renamed to src/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/frequency_queries_optimized.js

@@ -0,0 +1,68 @@
+[
+  {
+    "title": "Sample Test Case 0",
+    "input": [
+      [1, 5],
+      [1, 6],
+      [3, 2],
+      [1, 10],
+      [1, 10],
+      [1, 6],
+      [2, 5],
+      [3, 2]
+    ],
+    "expected": [0, 1]
+  },
+  {
+    "title": "Sample Test Case 1",
+    "input": [
+      [3, 4],
+      [2, 1003],
+      [1, 16],
+      [3, 1]
+    ],
+    "expected": [0, 1]
+  },
+  {
+    "title": "Sample Test Case 2",
+    "input": [
+      [1, 3],
+      [2, 3],
+      [3, 2],
+      [1, 4],
+      [1, 5],
+      [1, 5],
+      [1, 4],
+      [3, 2],
+      [2, 4],
+      [3, 2]
+    ],
+    "expected": [0, 1, 1]
+  },
+  {
+    "title": "Sample Test Case 3",
+    "input": [
+      [1, 3],
+      [1, 38],
+      [2, 1],
+      [1, 16],
+      [2, 1],
+      [2, 2],
+      [1, 64],
+      [1, 84],
+      [3, 1],
+      [1, 100],
+      [1, 10],
+      [2, 2],
+      [2, 1],
+      [1, 67],
+      [2, 2],
+      [3, 1],
+      [1, 99],
+      [1, 32],
+      [1, 58],
+      [3, 2]
+    ],
+    "expected": [1, 1, 0]
+  }
+]