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

import fs from 'fs'
import { numIdenticalPairs } from '../index.js'

// testlog is a log of test results
const testlog = []

// this first block matches with - Challenge 1
try {
    // Test cases:
    let testCase1 = [1, 2, 3, 1, 1, 3];
    let testCase2 = [1, 1, 1, 1];
    let testCase3 = [1, 2, 3];

    // Expected results:
    let expectedResult1 = 4;
    let expectedResult2 = 6;
    let expectedResult3 = 0;

    // Test the numIdenticalPairs function
    if (
      numIdenticalPairs(testCase1) === expectedResult1 &&
      numIdenticalPairs(testCase2) === expectedResult2 &&
      numIdenticalPairs(testCase3) === expectedResult3
    ) {
      testlog.push({ status: 'pass' });
    } else {
      throw new Error('Incorrect results for numIdenticalPairs function');
    }
  } catch (error) {
    testlog.push({
      status: 'error',
      error: error.message || 'Challenge 1 failed'
    })
  }

  // this second block matches with - Challenge 2
  try {
    if (numIdenticalPairs !== undefined) {
      testlog.push({ status: 'pass' });
    } else {
      throw new Error('numIdenticalPairs is not exported');
    }
  } catch (error) {
    testlog.push({
      status: 'error',
      error: error.message || 'Challenge 2 failed'
    })
  }

// very important for the final length of `testlog` array to match the number of challenges, in this case - 2.

// write the test log
fs.writeFileSync('/home/damner/code/.labtests/testlog.json', JSON.stringify(testlog))

// write the results array boolean. this will map to passed or failed challenges depending on the boolean value at the challenge index
fs.writeFileSync(process.env.UNIT_TEST_OUTPUT_FILE, JSON.stringify(testlog.map(result => result.status === 'pass')))

Setting up test environment script

#!/bin/bash
set -e 1

mkdir -p /home/damner/code/.labtests

cat > /home/damner/code/.labtests/package.json << EOF
{
    "type": "module"
}
EOF

cd /home/damner/code/.labtests
mv $TEST_FILE_NAME ./nodecheck.test.js

# import puppeteer doesn't work without it
npm link puppeteer

node 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']