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3 posts tagged with "counting"

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· One min read

https://leetcode.com/problems/ransom-note/

Solution 1​

/**
 * @param {string} ransomNote
 * @param {string} magazine
 * @return {boolean}
 */
var canConstruct = function (ransomNote, magazine) {
  const splitB = magazine.split('');

  for (let i = 0; i < ransomNote.length; i++) {
    const matchedIndex = splitB.indexOf(ransomNote[i]);
    if (matchedIndex !== -1) {
      splitB.splice(matchedIndex, 1);
    } else {
      return false;
    }
  }

  return true;
};

Runtime: 116 ms, faster than 76.45% of JavaScript online submissions for Ransom Note.

Memory Usage: 46.5 MB, less than 30.65% of JavaScript online submissions for Ransom Note.

· One min read

https://leetcode.com/problems/majority-element/

Solution 1​

/**
 * @param {number[]} nums
 * @return {number}
 */
var majorityElement = function (nums) {
  const element = {};

  for (const num of nums) {
    if (element[num]) {
      element[num]++;
    } else {
      element[num] = 1;
    }
  }

  let max = 0;
  let targetNum = '';

  for (let e in element) {
    if (element[e] > max) {
      max = element[e];
      targetNum = e;
    }
  }

  return Number(targetNum);
};

· One min read

https://leetcode.com/problems/first-unique-character-in-a-string/

Solution 1​

/**
 * @param {string} s
 * @return {number}
 */
var firstUniqChar = function (s) {
  const hashMap = {};
  for (let i = 0; i < s.length; i++) {
    if (hashMap[s[i]]) {
      hashMap[s[i]] = {
        ...hashMap[s[i]],
        count: hashMap[s[i]].count + 1,
      };
    } else {
      hashMap[s[i]] = {
        index: i,
        count: 1,
      };
    }
  }

  const filteredResult = Object.entries(hashMap)
    .map(([key, value]) => {
      if (value.count === 1) {
        return value.index;
      }
    })
    .filter((value) => value !== false && value !== undefined);

  return filteredResult.length === 0 ? -1 : filteredResult[0];
};