air work coding test

airwork.js

// Problem 1: Move Zeroes

function moveZeroToEnd(arr) {
  const count = {};

  const result = [];

  arr.forEach((element) => {
    count[element] = (count[element] || 0) + 1;
  });

  if (count[0] > 0) {
    for (let i = 0; i < count[0]; i++) {
      let index = arr.findIndex((item) => item === 0);
      delete arr[index];
      result.push(0);
    }
  }

  return arr.flat().concat(result);
}

console.log(moveZeroToEnd([0, 1, 0, 3, 12])); // [ 1, 3, 12, 0, 0 ]
console.log(moveZeroToEnd([0])); // [ 0 ]

// Problem 3: Find First Unique Character in a String

function findNonRepetaingChar(str) {
  let result;
  const count = {};

  Array.from(str).forEach((element) => {
    count[element.toLowerCase()] = (count[element.toLowerCase()] || 0) + 1;
  });

  const repeating = Object.entries(count);

  for (let index = 0; index < repeating.length; index++) {
    let item = repeating[index];
    if (item[1] === 1 && item[0] !== "") {
      result = item[0];

      break;
    } else {
      result = -1;
    }
  }

  return str.split("").findIndex((i) => i == result);
}

console.log(findNonRepetaingChar("Talent knows no boundaries")); // 2
console.log(findNonRepetaingChar("aabb")); // -1

// Problem 2: Intersection of Two Arrays

function intersection(nums1, nums2) {
  let set1 = new Set(nums1);

  let resultSet = new Set();

  for (let num of nums2) {
    if (set1.has(num)) {
      resultSet.add(num);
    }
  }

  return Array.from(resultSet);
}

console.log(intersection([1, 2, 2, 1], [2, 2])); // [2]
console.log(intersection([4, 9, 5], [9, 4, 9, 8, 4])); // [9, 4]

// union:    return [...new Set([...arr1, ...arr2])];


// first non-repeating character and then collects all non-repeating characters into an array:

const str = "swiss";

// Step 1: Build frequency map
const freq = {};
for (const char of str) {
  freq[char] = (freq[char] || 0) + 1;
}

// Step 2: Find first non-repeating character
let firstNonRepeating = null;
for (const char of str) {
  if (freq[char] === 1) {
    firstNonRepeating = char;
    break;
  }
}

// Step 3: Collect all non-repeating characters
const allNonRepeating = [];
for (const char of str) {
  if (freq[char] === 1) {
    allNonRepeating.push(char);
  }
}

console.log("First non-repeating character:", firstNonRepeating); // "w"
console.log("All non-repeating characters:", allNonRepeating);