Node.js 面试题目

// given an array
const arr = [1, 2, 3, 5, 6, 7, 4, 1];
// find a sum of (all numbers that are bigger or equal to 3)

const result = arr.filter((item) => item >= 3).reduce((a, b) => a + b);
console.log(result);

// given a string
const str = 'one two three two one one four five';
// return a count of duplicate words in that string

function countDuplicates(strVal) {
  const strArray = str.split(" ");
  const dictCount = {};
  for (const key of strArray) {
    if (!dictCount[key]) {
      dictCount[key] = 1;
      continue;
    }
    dictCount[key]++;
  }

  console.log(dictCount);

  let result = 0;
  for (const key of Object.keys(dictCount)) {
    if (dictCount[key] >= 2) {
      result++;
    }
  }
  return result;
}
console.log("result", countDuplicates(str)); // 2

// Write function that outputs the sorted concatenation of 2 sorted arrays.
// Example [1, 4, 9][2, 7, 11] => [1, 2, 4, 7, 9, 11]

function concatAndSort(arr1, arr2) {
  let point_1 = 0;
  let point_2 = 0;

  const result = [];

  console.log("arr1", arr1);
  console.log("arr2", arr2);

  while (point_1 < arr1.length || point_2 < arr2.length) {
    if (point_1 === arr1.length) {
      result.push(arr2[point_2]);
      point_2++;
      continue;
    }

    if (point_2 === arr2.length) {
      result.push(arr1[point_1]);
      point_1++;
      continue;
    }

    if (arr1[point_1] < arr2[point_2]) {
      result.push(arr1[point_1]);
      point_1++;
      continue;
    } else {
      result.push(arr2[point_2]);
      point_2++;
      continue;
    }
  }

  return result;
}

console.log(concatAndSort([1, 4, 9], [2, 7, 11, 12]));