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Programming Articles
Page 1293 of 2547
Counting numbers whose difference from reverse is a product of k in C++
We are given a range [l,r] and a number k. The goal is to find all the numbers between l and r (l
Read MoreHow to find the cumulative sums if a vector contains NA values in R?
The cumulative sums are the sum of consecutive values and we can take this sum for any numerical vector or a column of an R data frame. But if there exits an NA, then we need to skip it and therefore the size of the cumulative sums will be reduced by the number of NA values. If we have NA values in a vector then we can ignore them while calculating the cumulative sums with cumsum function by using !is.na.Examples> x1 x1Output[1] 1 2 3 4 5 6 7 8 9 10 NA > cumsum(x1[!is.na(x1)]) [1] 1 3 6 10 ...
Read MoreSum of the series 2^0 + 2^1 + 2^2 +...+ 2^n in C++
In this problem, we are given a number n which defines the n-th term of the series 2^0, 2^1, 2^2, …, 2^n. Our task is to create a program to find the sum of the series 2^0 + 2^1 + 2^2 +...+ 2^n.Let’s take an example to understand the problem, Inputn=6Output Explanation sum = 2^0 + 2^1 + 2^2 + 2^3 + 2^4 + 2^5 + 2^6 sum = 1 + 2 + 4 + 8 + 16 + 32 + 64 = 127A simple solution to the problem is by using the loop. Finding the 2^i, for each value from 0 ...
Read MoreCount ways to form minimum product triplets in C++
We are given with an array of numbers Arr[]. The goal is count the number of triplets whose product is equal to the smallest product of all possible triplets.Count triplets if (i
Read MoreHow to cut the elements of a numeric vector into multiple intervals in R?
A numeric vector may contain a large number of elements; therefore, we might want to convert that vector into a vector of intervals. For example, if we have 1 to 10 values in a vector then we might want to convert that vector into a vector of intervals such as (1, 5) for 1, 2, 3, 4, and 5 and (6, 10) for 6, 7, 8, 9, 10). This can be done by using cut function where we will use breaks argument to combine the vector elements in an interval.Examples> x1 x1Output[1] 1 2 3 4 5 6 7 8 ...
Read MoreCount of pairs in an array whose sum is a perfect square in C++
We are given with an array of N elements. The goal is to find the count of all pairs (Arr[i], Arr[j]) which have a sum which is a perfect square such that i!=j. That is Arr[i]+Arr[j] is a perfect square.We will do this by calculating the sum of pairs and check if the square root of that sum is equal to the floor value of the square root. sqrt(Arr[i]+Arr[j])-floor( sqrt(Arr[i]+Arr[j] )==0.Let’s understand with examples.Input − Arr[]= { 4, 3, 2, 1, 2, 4 } N=6Output − Count of pairs with sum as perfect square − 2Explanation −Arr[1]+Arr[3]=4, sqrt(4)-floor(4)=0 4 is ...
Read MoreMaximum number of dots after throwing a dice N times in C++
Given the task is to calculate the maximum number of dots that can be expected after throwing a dice N times having M faces.The first face of the dice contains 1 dot, the second face has 2 dots and so on. Likewise the M-th face contains M number of dots.The probability of appearance of each face becomes 1/M.Let’s now understand what we have to do using an example −Input − M=2, N=3Output − 1.875Explanation − The dice has 2 sides = {1, 2}If the dice is thrown 3 times then the sample space will be = MN = 23{(1, 1, ...
Read MoreCount unordered pairs (i,j) such that product of a[i] and a[j] is power of two in C++
We are given with an array of N elements. The goal is to find the count of all pairs (Arr[i], Arr[j]) which have a sum which is a perfect square such that i!=j. That is Arr[i]+Arr[j] is a perfect square.We will do this by calculating the sum of pairs and check if the square root of that sum is equal to the floor value of the square root. sqrt(Arr[i]+Arr[j])-floor( sqrt(Arr[i]+Arr[j] )==0.Let’s understand with examples.Input − Arr[]= { 4, 3, 2, 1, 2, 4 } N=6Output − Count of pairs with sum as perfect square − 2Explanation −Arr[1]+Arr[3]=4, sqrt(4)-floor(4)=0 4 is ...
Read MoreHow to change the row index after sampling an R data frame?
When we take a random sample from an R data frame the sample rows have row numbers as in the original data frame, obviously it happens due to randomization. But it might create confusion while doing analysis, especially in cases when we need to use rows, therefore, we can convert the index number of rows to numbers from 1 to the number of rows in the selected sample.ExampleConsider the below data frame −> set.seed(111) > x1 x2 x3 df1 df1Output x1 x2 x3 1 1.735220712 2.8616625 1.824274 2 1.169264128 2.8469644 1.878784 ...
Read MoreExamples of soft references and phantom references?
Soft references are often used to implement memory-sensitive caches. Let us see an example of soft references in Java −Exampleimport java.lang.ref.SoftReference; class Demo{ public void display_msg(){ System.out.println("Hello there"); } } public class Demo_example{ public static void main(String[] args){ Demo my_instance = new Demo(); my_instance.display_msg(); SoftReference my_softref = new SoftReference(my_instance); my_instance = null; my_instance = my_softref.get(); my_instance.display_msg(); } }OutputHello there Hello thereA class named Demo contains a function named ‘display_msg’, that displays the relevant message. Another ...
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