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Suppose we want to make a data structure that has two methods −add(val) this adds the value val to the data structurefind(val) this checks whether there are two elements whose sum is val or notWe have to design this so that we can get the result on the fly. We will not search for numbers every time when a query comes.So, if the input is like create an object obj and add few numbers 6, 14, 3, 8, 11, 15, then check like obj.find(9), obj.find(11), obj.find(15), then the output will be True, True, False as 9 can be formed with ... Read More
Suppose we have two strings s and t. We want to form t, but there are some problems in the keyboard where some of characters stuck so they may be written 1 or more times. We have to check whether it's possible that typed s was meant to write t or not.So, if the input is like s = "appppleee" t = "apple", then the output will be True.To solve this, we will follow these steps −i := 0, j := 0s_len := size of st_len := size of tt_last := blank stringwhile j < t_len, doif i is same ... Read More
Suppose we have a list of numbers called nums. We have to check whether the list alternates starting from strictly increasing then strictly decreasing and then strictly increasing and so on. And also if the list is only strictly increasing, it will be valid.So, if the input is like nums = [2, 4, 8, 7, 5, 1, 5, 7, 2, 1], then the output will be True, because [2, 4, 8] are increasing, then [7, 5, 1] is decreasing, then again [5, 7] is increasing and [2, 1] is decreasing.To solve this, we will follow these steps −if nums[1] = ... Read More
Suppose we have a list of numbers called nums, where elements are sorted in ascending order, we have to square the elements and return the result in sorted order.So, if the input is like nums = [-8, -3, 0, 5, 6], then the output will be [0, 9, 25, 36, 64]To solve this, we will follow these steps −n := size of numsl := 0r := n - 1index := n - 1res := a list of size same as nums and fill it with 0while index >= 0, doif |nums[l]| > |nums[r]|, thenres[index] := nums[l] * nums[l]l := l ... Read More
Suppose we have a lists of numbers in nums. We have to sort the list in ascending order by the number of 1s present in the binary representation for each number. If two numbers have same number of 1s, then arrange them based on their values.So, if the input is like nums = [4, 1, 12, 7, 6], then the output will be [1, 4, 6, 12, 7], because −Binary form of 4 is 0100Binary form of 1 is 0001Binary form of 6 is 0110Binary form of 12 is 1100Binary form of 7 is 0111So the arrangement is [1, 4, ... Read More
Suppose we have a list of numbers called. Now let us consider any pair of indices (i, j) where i < j and j - i > 1. Then find the smallest pair sum.So, if the input is like nums = [3, 4, 2, 2, 4], then the output will be 5, we can select values 3 and 2 so the total sum is 5. We cannot select 2 and 2 because they are adjacent, and violating the j - i > 1 constraint.To solve this, we will follow these steps −n := size of numsmin_seen := nums[0]ans := inffor ... Read More
Suppose we have a string s with four possible characters "1", "2", "3" and "?". We can place any one of "1", "2" and "3", in the place of "?". We have to find the smallest possible number that we can make such that no two adjacent digits are same.So, if the input is like s = "2??3?", then the output will be 21231To solve this, we will follow these steps −i := 0s := a list of elements from sif size of s < 2, thenif s[i] is same as "?", thenreturn "1"while i < size of s, doif ... Read More
Suppose we have a list of numbers called nums. If the frequency of a most frequent number in nums is k. We have to find the length of a shortest sublist such that the frequency of its most frequent item is also k.So, if the input is like nums = [10, 20, 30, 40, 30, 10], then the output will be 3, because here the most frequent numbers are 10 and 30 , here k = 2. If we select the sublist [30, 40, 30] this is the shortest sublist where 30 is present and its frequency is also 2.To ... Read More
Suppose we have a list of numbers called nums, where n elements are present. We have to chesk whether we can make a list with first n natural numbers either in increasing or decreasing fashion, like [1, 2, ..., n] or [n, n - 1, ..., 1] by shifting nums to the right any number of times or not.So, if the input is like nums = [5, 6, 1, 2, 3, 4], then the output will be True, because we can shift them four times to make the array [1, 2, 3, 4, 5, 6]To solve this, we will follow ... Read More
Suppose we want to implement a set data structure with the following methods −Constructor to construct a new instance of a setadd(val) to insert integer val into the setexists(val) to check whether val is in the set or notremove(val) to remove the val from the setSo, if we construct a set s, then call s.add(10), s.add(20), s.add(10), s.exists(10), s.remove(10), s.exists(10), s.exists(20), then the output will befor s.add(10) it will insert 10for s.add(20) it will insert 2010 is already in s, so nothing will happens.exists(10) will return true as 10 is thereDelete 10 by s.remove(10)s.exists(10) will return false because 10 is ... Read More