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code-base.md

Weekly Leet Code Challenage

Every week we will have an easy leet code question, posted on every friday. and on the same day we will share the code for the previous challenage :)

Weekly Leet Code 771. Jewels and Stones

From Minjoo (Javascript) O(n2)

var numJewelsInStones = function(J, S) {
    var count = 0;
    var array = S.split('');
    for(var i = 0; i<J.length; i++){
        count += array.filter(char => char == J.charAt(i)).length;
    }
    return count;
};

From Xinyi (GoLang) O(n)

func numJewelsInStones(J string, S string) int {
	result, jewelBook := 0, map[rune]int{}
	for _, letter := range J { jewelBook[letter] = 1 }
	for _, s := range S { result += jewelBook[s] }
	return result
}

From FlipeB (Golang) O(n)

func numJewelsInStones(J string, S string) int {
        count, m := 0, make(map[rune]bool)
        for _,j := range J {
                m[j]=true
        }
        for _,s := range S {
                if(m[s]) {count=count+1}
        }
        return count
}

From Suguru (JavaScript) O(n)

/**
 * @param {string} J
 * @param {string} S
 * @return {number}
 */
function numJewelsInStones(J, S) {
  const map = {};
  for (let i = 0; i < S.length; i++) {
    const c = S[i];
    map[c] = ++map[c] || 1;
  }
  let result = 0;
  for (let i = 0; i < J.length; i++) {
    const n = map[J[i]];
    if (n) {
      result += n;
    }
  }
  return result;
}

Weekly Leet Code Find All Numbers Disappeared

From Minjoo (Javascript) O(n2)

/**
 * @param {number[]} nums
 * @return {number[]}
 */
var findDisappearedNumbers = function(nums) {
    var toRet = [];
    for(var i = 1; i<nums.length+1; i++){
        if(!nums.includes(i)) toRet.push(i);
    }
    return toRet;
};

From ~Josh the man (C#) O(n)

using System.Linq;


public class Solution
{
    public IList<int> FindDisappearedNumbers(int[] nums)
    {
        return Enumerable.Range(1, nums.Length).Except(nums.Distinct()).ToList();
        
    }
}

BEAT EVERYBODY IN C# BABY FIRST LEETCODE!

From Xinyi (Golang) O(n)

func findDisappearedNumbers(nums []int) []int {
	result := []int{}
	// mark as many numbers to negative as much as possible
	for _, value := range nums {
		nums[abs(value)-1] = -abs(nums[abs(value)-1])
	}
	// find position and get the index
	for index, value := range nums {
		if value > 0 { 
			result = append(result, index + 1)
		}
	}
	return result
}
func abs(val int) int {
	return int(math.Abs(float64(val)))
 }

From Felipe (Golang) O(n)

func findDisappearedNumbers(nums []int) []int {
    a, r := make([]int, len(nums)), []int{}
           for _,n := range nums {
                   a[n-1] = 1
           }
   
           for i,n := range a {
                   if (n == 0){
                           r = append(r,i+1)
                   }
           }
           return (r)
}   

Weekly LeetCode Question: Rotate String

From Xinyi (Swift) O(n)

class Solution {
    var i = 0
    func rotateString(_ A: String, _ B: String) -> Bool {
      if A == B { return true }
      if i == A.count { return false }
      i += 1
      return rotateString(A.shiftLeft, B)
    } 
}

extension String {
    var shiftLeft: String {
        let index = self.startIndex
        let nextIndex = self.index(index, offsetBy: 1)
        return String(self[nextIndex...] + self[...index])
    }
}

From Josh the Man (C#)

{
    public bool RotateString(string A, string B)
    {
       return (A+A).Contains(B);
    }
    
}

Beats 37% :( Next time I have to learn how to define my RotateString. NEXT ONE!