Suppose we have a list of numbers called nums. We have to find the number of index pairs i, j, where i < j such that nums[i] + nums[j] is equal to 2^k for some 0 >= k.So, if the input is like nums = [1, 2, 6, 3, 5], then the output will be 3, as there are three pairs sum like (6, 2): sum is 8, (5, 3): sum is 8 and (1, 3) sum is 4To solve this, we will follow these steps −res := 0c := a map containing frequencies of each elements present infor each ... Read More

Suppose we have a numeric string s. We have to check whether there is some arrangement where we can have one pair of the same character and the rest of the string form any number of triplets of the same characters.So, if the input is like s = "21133123", then the output will be True, because there are two 2s to form "22" as the pair and "111", "333" as two triplets.To solve this, we will follow these steps −d := a list containing frequencies of each elements present in sfor each k in d, dod[k] := d[k] - 2if ... Read More

Suppose we have alphanumeric string s. It can hold both uppercase or lowercase letters. We have to check whether s is a palindrome or not considering only the lowercase alphabet characters.So, if the input is like s = "rLacHEec0a2r8", then the output will be True because the string contains "racecar" in lowercase, which is a palindrome.To solve this, we will follow these steps −x := blank stringfor each character i in s, doif i is in lowercase, thenx := x concatenate ireturn true when x is palindrome, otherwise falseExampleLet us see the following implementation to get better understandingdef solve(s):   ... Read More

Suppose we have a list called relations. Where each element in relations list relations[i] contains two numbers [ai, bi] it indicates person ai is following bi on a social media platform. We have to find the list of people who follow someone and they follow them back, we have to return it in sorted sequence.So, if the input is like relations = [[0, 2], [2, 3], [2, 0], [1, 0]], then the output will be [0, 2].To solve this, we will follow these steps −ans := a new setseen := a new setfor each pair a and b in relations, ... Read More

Suppose we have a lowercase string s. We have to find the minimum numbers of contiguous substrings in which s is divided into parts such that each substring is either non-increasing or non-decreasing. So for example, if the string is like "pqqqr" is a non-decreasing string, and "qqqp" is a non-increasing string.So, if the input is like s = "pqrsrqp", then the output will be 2, because we can break s like "pqrs" and "rqp".To solve this, we will follow these steps −if s is empty, thenreturn 0last := s[0]direction := 1count := 1for each char in s, doif char ... Read More

Suppose we have a list of numbers called nums. We have to find the minimum positive value that we can insert at the beginning of nums so that that prefix sums of the resulting list contains numbers that are all larger than 0.So, if the input is like nums = [3, -6, 4, 3], then the output will be 4, because if we insert 4 to the list then we have [4, 3, -6, 4, 3]. Now the prefix sums are then [4, 7, 1, 5, 8], all are larger than 0.To solve this, we will follow these steps −insert ... Read More

Suppose we have three strings text, w1, and w2. The text is a sentence with different words. We have to find the smallest distance between any two occurrences of w1 and w2 in the text, the distance is measured in number of words in between them. If either w1 or w2 is not present in text, return -1.So, if the input is like text = "joy happy power happy joy joy power happy limit" w1 = "power" w2 = "limit", then the output will be 1, as there is only one word "happy" in between the power and limit.To solve ... Read More

Suppose we have a lit of numbers called nums, and have another value k. If we remove k elements from nums, then find the minimum of (maximum of nums - minimum of nums).So, if the input is like nums = [4, 10, 3, 2, 8, 9] k = 3, then the output will be 2, because if we remove 10, 8 and 9 then maximum is 4, minimum is 2 so difference is 2.To solve this, we will follow these steps −sort the list numsp := size of nums - km := (last element of nums) - nums[0]for i in ... Read More

Suppose we have a list of numbers called nums and a value k. First we shall remove a sublist of size k, then find the minimum of (maximum of nums - minimum of nums).So, if the input is like nums = [2, 3, 10, 9, 8, 4] k = 3, then the output will be 2, If we remove [10, 9, 8] we get [2, 3, 4] and 4 - 2 = 2To solve this, we will follow these steps −N := size of numscopy nums into lmin and lmaxalso copy nums into rmin and rmaxfor i in range 1 ... Read More

Suppose we have a number n, we have to find the maximum number we can get by inserting 5 anywhere in the number.So, if the input is like n = 834, then the output will be 8534.To solve this, we will follow these steps −if n > 0, thens := n as stringk := blank stringc := Falsefor each character i in s, doif i < 5 and c is False, thenk := k concatenate "5" concatenate ic := Trueotherwise, k := k concatenate ireturn k as integerotherwise, k := blank strings := |n| as stringc := Falsefor each character ... Read More