DEV Community: Karleb

#2037. Minimum Number of Moves to Seat Everyone

Karleb — Thu, 13 Jun 2024 09:18:47 +0000

https://leetcode.com/problems/minimum-number-of-moves-to-seat-everyone/description/?envType=daily-question&envId=2024-06-13


/**
 * @param {number[]} seats
 * @param {number[]} students
 * @return {number}
 */
var minMovesToSeat = function (seats, students) {
    let res = 0

    seats.sort((a, b) => b - a)
    students.sort((a, b) => b - a)

    for (let i = 0; i < seats.length; i++) {
        //the cost of moving a student is the absolute difference between their current position and the target seat position
        //pair the closest seats with the closest students.
        res += Math.abs(seats[i] - students[i])
    }

    return res
};

#75. Sort Colors

Karleb — Thu, 13 Jun 2024 09:10:18 +0000

https://leetcode.com/problems/sort-colors/description/?envType=daily-question&envId=2024-06-13


var sortColors = function(nums) {
  let low = 0, mid = 0, high = nums.length - 1

  while (mid <= high) {
    if (nums[mid] === 0) {
        [nums[low], nums[mid]] = [nums[mid], nums[low]]
        low++
        mid++
    } else if (nums[mid] === 1) {
        mid++
    } else {
         [nums[mid], nums[high]] = [nums[high], nums[mid]]
         high--
    }
  }
};

#1122. Relative Sort Array

Karleb — Tue, 11 Jun 2024 00:52:59 +0000

https://leetcode.com/problems/relative-sort-array/description/?envType=daily-question&envId=2024-06-11


/**
 * @param {number[]} arr1
 * @param {number[]} arr2
 * @return {number[]}
 */
var relativeSortArray = function(arr1, arr2) {
    const map = new Map()
    const N = arr2.length

    for(let i = 0; i < arr2.length; i++) {
        map.set(arr2[i], i)
    }

    return arr1.sort((a,b) => {
        a = map.has(a) ? map.get(a) : N + a
        b = map.has(b) ? map.get(b) : N + b
        return a - b
    })
};

#1051. Height Checker

Karleb — Tue, 11 Jun 2024 00:51:25 +0000

https://leetcode.com/problems/height-checker/description/?envType=daily-question&envId=2024-06-11


/**
 * @param {number[]} heights
 * @return {number}
 */
var heightChecker = function (heights) {
    let res = 0
    let expected = heights.slice().sort((a, b) => a - b)

    for (let i = 0; i < heights.length; i++) {
        if (heights[i] !== expected[i]) res++
    }

    return res
};

#974. Subarray Sums Divisible by K

Karleb — Tue, 11 Jun 2024 00:48:37 +0000

https://leetcode.com/problems/subarray-sums-divisible-by-k/description/?envType=daily-question&envId=2024-06-11


/**
 * @param {number[]} nums
 * @param {number} k
 * @return {number}
 */

var subarraysDivByK = function(nums, k) {
  let prefixMod = 0;
  let result = 0;
  const modGroups = new Array(k).fill(0);
  modGroups[0] = 1;

  for (const num of nums) {
    // Take modulo twice to avoid negative remainders.
    prefixMod = (prefixMod + num % k + k) % k;
    result += modGroups[prefixMod];
    modGroups[prefixMod]++;
  }

  return result;
}

#523. Continuous Subarray Sum

Karleb — Tue, 11 Jun 2024 00:46:05 +0000

https://leetcode.com/problems/continuous-subarray-sum/description/?envType=daily-question&envId=2024-06-11


js

/**
 * @param {number[]} nums
 * @param {number} k
 * @return {boolean}
 */
var checkSubarraySum = function(nums, k) {
    let sum = 0
    const remainderMap = new Map()
    remainderMap.set(0, -1)

    for(let i = 0; i < nums.length; i++) {
        sum += nums[i]

        let remainder = sum % k

        remainder = remainder < 0 ? remainder + k : remainder

        if (remainderMap.has(remainder)) {
            if (i - remainderMap.get(remainder) > 1) return true
        } else {
            remainderMap.set(remainder, i)
        }
    }

    return false
};

#648. Replace Words

Karleb — Fri, 07 Jun 2024 20:16:32 +0000

https://leetcode.com/problems/replace-words/description/?envType=daily-question&envId=2024-06-07


/**
 * @param {string[]} dictionary
 * @param {string} sentence
 * @return {string}
 */
var replaceWords = function(dictionary, sentence) {
    sentence = sentence.split(" ")

    for (let i = 0; i < sentence.length; i++) {
        for (let j = 0; j < dictionary.length; j++) {
            if (sentence[i].startsWith(dictionary[j])) {
                sentence[i] = dictionary[j]
            }
        }
    }

    return sentence.join(" ")
};

#846. Hand of Straights

Karleb — Thu, 06 Jun 2024 15:52:16 +0000

https://leetcode.com/problems/hand-of-straights/?envType=daily-question&envId=2024-06-06

/**
 * @param {number[]} hand
 * @param {number} groupSize
 * @return {boolean}
 */

 function findSuccessors(hand, groupSize, i, n) {
    let next =  hand[i] + 1
    hand[i] = -1
    let count = 1
    i++

    while(i < n && count < groupSize) {
        if (hand[i] === next) {
            next = hand[i] + 1
            hand[i] = -1
            count++
        }
        i++
    }

    return count === groupSize
}

var isNStraightHand = function (hand, groupSize) {
    let n = hand.length

    if (n % groupSize !== 0) return false

    hand.sort((a, b) => a - b)

    for (let i = 0; i < hand.length; i++) {
        if (hand[i] !== -1) {
            if (! findSuccessors(hand, groupSize, i, n)) return false
        }
    }

    return true
};

#846. Hand of Straights

Karleb — Thu, 06 Jun 2024 15:51:49 +0000

https://leetcode.com/problems/hand-of-straights/?envType=daily-question&envId=2024-06-06

/**
 * @param {number[]} hand
 * @param {number} groupSize
 * @return {boolean}
 */

 function findSuccessors(hand, groupSize, i, n) {
    let next =  hand[i] + 1
    hand[i] = -1
    let count = 1
    i++

    while(i < n && count < groupSize) {
        if (hand[i] === next) {
            next = hand[i] + 1
            hand[i] = -1
            count++
        }
        i++
    }

    return count === groupSize
}

var isNStraightHand = function (hand, groupSize) {
    let n = hand.length

    if (n % groupSize !== 0) return false

    hand.sort((a, b) => a - b)

    for (let i = 0; i < hand.length; i++) {
        if (hand[i] !== -1) {
            if (! findSuccessors(hand, groupSize, i, n)) return false
        }
    }

    return true
};

#344. Reverse String

Karleb — Sun, 02 Jun 2024 16:04:48 +0000

https://leetcode.com/problems/reverse-string/description/?envType=daily-question&envId=2024-06-02


/**
 * @param {character[]} s
 * @return {void} Do not return anything, modify s in-place instead.
 */
var reverseString = function(s) {
    let start  = 0, end = s.length - 1

    while(start < end) {
        // let ch = s[start]
        // s[start] = s[end]
        // s[end] = ch

        [s[start], s[end]] = [s[end], s[start]]

        start++
        end--
    }
};

3110. Score of a String

Karleb — Sat, 01 Jun 2024 06:50:40 +0000

https://leetcode.com/problems/score-of-a-string/?envType=daily-question&envId=2024-06-01

/**
 * @param {string} s
 * @return {number}
 */
var scoreOfString = function(s) {
    let res = 0

    for(let i = 0; i < s.length - 1; i++) {
       res += Math.abs(s[i].charCodeAt(0) - s[i + 1].charCodeAt(0))
    }

    return res
};

#260. Single Number III

Karleb — Fri, 31 May 2024 09:28:32 +0000

https://leetcode.com/problems/single-number-iii/description/?envType=daily-question&envId=2024-05-31

/**
 * @param {number[]} nums
 * @return {number[]}
 */
var singleNumber = function (nums) {
    if (nums.length === 2) return nums

    const map = new Map()
    const res = []

    for (let num of nums) {
        map.set(num, (map.get(num) || 0) + 1);
    }

    for (let [key, value] of map) {
        if (value === 1) {
            res.push(
                key
            )
        }
    }

    return res
};