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Suppose, we have a string with digits like this −const str = '11222233344444445666';We are required to write a JavaScript function that takes in this string and returns an object that represents the count of each number in the string.So, for this string, the output should be −const output = { "1": 2, "2": 4, "3": 3, "4": 7, "5": 1, "6": 3 };Therefore, let’s write the code for this function −ExampleThe code for this will be −const str = '11222233344444445666'; const mapString = str => { const map = {}; for(let i ... Read More
Suppose we have two values start and end, we have to find the minimum number of operations needed to convert start to end by using these operations −Decrement by 1Multiply by 2So, if the input is like start = 2, end = 7, then the output will be 3, as we can multiply 2 to get 4, then multiply 2 to get 8 and then subtract 1 to get 7.To solve this, we will follow these steps −ans := 0Do the following infinitely, doif end
We are required to write a JavaScript function that takes in an array of numbers that may contain some duplicate numbers. Our function should return the sum of all the unique elements (elements that only appear once in the array) present in the array.For exampleIf the input array is −const arr = [2, 5, 5, 3, 2, 7, 4, 9, 9, 11];Then the output should be 25.We will simply use a for loop, iterate the array and return the sum of unique elements.ExampleThe code for this will be −const arr = [2, 5, 5, 3, 2, 7, 4, 9, 9, ... Read More
Suppose, we have an array of objects like this −const arr = [{a: 2, b: 5, c: 6}, {a:3, b: 4, d:1}, {a: 1, d: 2}];Each object is bound to have unique in itself (for it to be a valid object), but two different objects can have the common keys (for the purpose of this question).We are required to write a JavaScript function that takes in one such array and returns an object with all the unique keys present in the array and their values cumulative sum as the value.So, the resultant object should look like −const output = {a: ... Read More
Suppose we have one binary tree. We have to check whether the tree is symmetric tree or not. A tree will be said to be symmetric if it is same when we take the mirror image of it. From these two trees, the first one is symmetric, but second one is not.To solve this, we will follow these steps.We will call following steps recursively. The function will be solve(root, root)if the node1 and node2 are empty, then return trueif either node1 or node2 is empty, then return falsereturn true when node1.val = node2.val and solve(node1.left, node2.right) and solve(node1.right, node2.left)Let us ... Read More
Suppose we have an object like this −const obj = { key1: 56, key2: 67, key3: 23, key4: 11, key5: 88 };We are required to write a JavaScript function that takes in this object and returns a sorted array like this −const arr = [11, 23, 56, 67, 88];Here, we sorted the object values and placed them in an array.Therefore, let’s write the code for this function −ExampleThe code for this will be −const obj = { key1: 56, key2: 67, key3: 23, key4: 11, key5: 88 }; const sortObject ... Read More
We are required to write a JavaScript function that takes in an array of String / Number literals and returns a subarray of all the elements that were palindrome in the original array.For exampleIf the input array is −const arr = ['carecar', 1344, 12321, 'did', 'cannot'];Then the output should be −const output = [12321, 'did'];We will create a helper function that takes in a number or a string and checks if its a boolean or not.Then we will loop over the array, filter the palindrome elements and return the filtered array.Therefore, let’s write the code for this function −ExampleThe code ... Read More
Suppose we have two trees, we have to check whether we can transform first tree into second one by swapping any node's left and right subtrees any number of times.So, if the input is likethen the output will be TrueTo solve this, we will follow these steps −que1 := a queue with root0 initiallyque2 := a queue with root1 initiallywhile que1 and que2 are not empty, dotemp1 := a new list, temp2 := a new listvalues1 := a new list, values2 := a new listif que1 and que2 are containing different number of elements, thenreturn Falsefor i in range 0 ... Read More
Suppose we have a binary tree, we have to check whether for every node in the tree except leaves, its value is same as the sum of its left child's value and its right child's value or not.So, if the input is likethen the output will be TrueTo solve this, we will follow these steps −Define a function dfs() . This will take rootif root is null, thenreturn Trueif left of root is null and right of root is null, thenreturn Trueleft := 0if left of root is not null, thenleft := value of left of rootright := 0if right ... Read More
Suppose we have a list of numbers called nums and another value k, we have to find three unique entries in nums (a, b, c) such that |a + b + c − k| is minimized and return the absolute difference.So, if the input is like nums = [2, 5, 25, 6] k = 14, then the output will be 1 as if we take [2, 5, 6] will get us closest to 14 and the absolute difference is |13 − 14| = 1.To solve this, we will follow these steps −sort the list numsans := 1^9for i in range ... Read More