Number of Good Pairs Lab

In this lab, you will be implementing a function called numIdenticalPairs that counts the number of good pairs in a given array of integers. A pair (i, j) is called good if nums[i] == nums[j] and i < j.

The function should have the following signature:

/**
 * @param {number[]} nums
 * @return {number}
 */
function numIdenticalPairs(nums) {
  // Your code here
}

Your implementation should meet the following requirements:

• It takes an array of integers nums as input.
• The input array will have a length between 1 and 100.
• The elements in the input array will have values between 1 and 100.
• It returns the number of good pairs in the input array.

Example 1:

Input: nums = [1, 2, 3, 1, 1, 3] Output: 4 Explanation: There are four good pairs (0, 3), (0, 4), (3, 4), (2, 5) 0-indexed.

Example 2:

Input: nums = [1, 1, 1, 1] Output: 6 Explanation: Each pair in the array are good.

Example 3:

Input: nums = [1, 2, 3] Output: 0

Make sure to export the function so that it can be used by the evaluation script:

export { numIdenticalPairs };

Challenges

1. Implement the numIdenticalPairs function.
2. Export the numIdenticalPairs function.

Evaluation script

1import fs from 'fs'
2import { numIdenticalPairs } from '../index.js'
3
4// testlog is a log of test results
5const testlog = []
6
7// this first block matches with - Challenge 1
8try {
9    // Test cases:
10    let testCase1 = [1, 2, 3, 1, 1, 3];
11    let testCase2 = [1, 1, 1, 1];
12    let testCase3 = [1, 2, 3];
13
14    // Expected results:
15    let expectedResult1 = 4;
16    let expectedResult2 = 6;
17    let expectedResult3 = 0;
18
19    // Test the numIdenticalPairs function
20    if (
21      numIdenticalPairs(testCase1) === expectedResult1 &&
22      numIdenticalPairs(testCase2) === expectedResult2 &&
23      numIdenticalPairs(testCase3) === expectedResult3
24    ) {
25      testlog.push({ status: 'pass' });
26    } else {
27      throw new Error('Incorrect results for numIdenticalPairs function');
28    }
29  } catch (error) {
30    testlog.push({
31      status: 'error',
32      error: error.message || 'Challenge 1 failed'
33    })
34  }
35
36  // this second block matches with - Challenge 2
37  try {
38    if (numIdenticalPairs !== undefined) {
39      testlog.push({ status: 'pass' });
40    } else {
41      throw new Error('numIdenticalPairs is not exported');
42    }
43  } catch (error) {
44    testlog.push({
45      status: 'error',
46      error: error.message || 'Challenge 2 failed'
47    })
48  }
49
50// very important for the final length of `testlog` array to match the number of challenges, in this case - 2.
51
52// write the test log
53fs.writeFileSync('/home/damner/code/.labtests/testlog.json', JSON.stringify(testlog))
54
55// write the results array boolean. this will map to passed or failed challenges depending on the boolean value at the challenge index
56fs.writeFileSync(process.env.UNIT_TEST_OUTPUT_FILE, JSON.stringify(testlog.map(result => result.status === 'pass')))

Setting up test environment script

1#!/bin/bash
2set -e 1
3
4mkdir -p /home/damner/code/.labtests
5
6cat > /home/damner/code/.labtests/package.json << EOF
7{
8    "type": "module"
9}
10EOF
11
12cd /home/damner/code/.labtests
13mv $TEST_FILE_NAME ./nodecheck.test.js
14
15# import puppeteer doesn't work without it
16npm link puppeteer
17
18node nodecheck.test.js 2>&1 | tee evaluationscript.log

Initial file system for user

/**
 * @param {number[]} nums
 * @return {number}
 */
function numIdenticalPairs(nums) {
  // Your code here
}

// Make sure to export numIdenticalPairs function
export { numIdenticalPairs };

{
    "name": "codedamn-lab",
    "type": "module"
}

tabs: ['index.js']
terminals: ['yarn install']