├── leetcode-1480-day1.js
├── leetcode-1491-day2.js
├── leetcode-1539-day3.js
└── leetocde-1636-day4.js


/leetcode-1480-day1.js:
--------------------------------------------------------------------------------
 1 | /**
 2 |  * @param {number[]} nums
 3 |  * @return {number[]}
 4 |  */
 5 | var runningSum = function(nums) {
 6 |   let sum = 0;
 7 |   for (let i = 0; i < nums.length; i++) {
 8 |     sum = sum + nums[i];
 9 |     nums[i] = sum;
10 |   }
11 |   return nums;
12 | };
13 | 
14 | // Time complexity O(n)
15 | // Space Complexity O(1)
16 | 


--------------------------------------------------------------------------------
/leetcode-1491-day2.js:
--------------------------------------------------------------------------------
 1 | var average = function(salary) {
 2 |   let averageSalary = 0;
 3 |   let min = Number.MAX_VALUE;
 4 |   let max = 0;
 5 |   for (let i = 0; i < salary.length; i++) {
 6 |     if (salary[i] < min) min = salary[i];
 7 |     if (salary[i] > max) max = salary[i];
 8 |     averageSalary += salary[i];
 9 |   }
10 |   averageSalary = (averageSalary - min - max) / (salary.length - 2);
11 |   return averageSalary;
12 | };
13 | 
14 | // Time complexity O(n)
15 | // Space Complexity O(1)
16 | 


--------------------------------------------------------------------------------
/leetcode-1539-day3.js:
--------------------------------------------------------------------------------
 1 | /**
 2 |  * @param {number[]} arr
 3 |  * @param {number} k
 4 |  * @return {number}
 5 |  */
 6 | var findKthPositive = function(arr, k) {
 7 |   let missingPrev = arr[0] - 1;
 8 |   let missingSoFar = arr[0] - 1;
 9 |   let missing;
10 |   let elementPresentInArrayRange = false; // check if missing element found in array range
11 |   if (k < arr[0]) {
12 |     //if missing element present before forst element
13 |     return k;
14 |   }
15 |   for (let i = 1; i < arr.length; i++) {
16 |     // between 4 7 there are 7 - 4 - 1 = 2 missing numbers
17 |     missingSoFar = missingSoFar + arr[i] - arr[i - 1] - 1;
18 |     if (missingSoFar >= k) {
19 |       missing = arr[i - 1] + k - missingPrev;
20 |       elementPresentInArrayRange = true;
21 |       break;
22 |     }
23 |     missingPrev = missingSoFar;
24 |   }
25 |   //missing element present outside array range
26 |   if (!elementPresentInArrayRange === false)
27 |     return arr[arr.length - 1] + k - missingSoFar;
28 |   return missing;
29 | };
30 | 
31 | // Time complexity O(n)
32 | // Space Complexity O(1)
33 | 


--------------------------------------------------------------------------------
/leetocde-1636-day4.js:
--------------------------------------------------------------------------------
 1 | /**
 2 |  * @param {number[]} nums
 3 |  * @return {number[]}
 4 |  */
 5 | var frequencySort = function(nums) {
 6 |   let frequency = {};
 7 |   // find out frequency of every element
 8 |   // for input [1,1,2,2,2,3]
 9 |   // frequency = {'1' : 2, '2' : 3; '3' : 1}
10 |   for (let i = 0; i < nums.length; i++) {
11 |     if (frequency[nums[i]]) frequency[nums[i]]++;
12 |     else frequency[nums[i]] = 1;
13 |   }
14 | 
15 |   // frequency = [[1,2],[2,3],[3,1]]
16 |   frequency = Object.entries(frequency);
17 | 
18 |   // sort the above array based on frequency
19 |   // [[2,3],[1,2],[3,1]]
20 |   frequency.sort(function(a, b) {
21 |     if (a[1] != b[1]) return a[1] - b[1];
22 |     else return b[0] - a[0];
23 |   });
24 | 
25 |   // create the new array based on top result
26 |   let index = 0;
27 |   for (let i = 0; i < frequency.length; i++) {
28 |     for (let j = 0; j < frequency[i][1]; j++) {
29 |       nums[index++] = frequency[i][0];
30 |     }
31 |   }
32 |   return nums;
33 | };
34 | 
35 | // Time complexity O(nlogn) best sorting algo is nlogn time
36 | // Space Complexity O(n) for frequency
37 | 


--------------------------------------------------------------------------------