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Programming Articles
Page 1243 of 2547
Palindrome Permutation II in C++
Suppose we have a string s, we have to find all the palindromic permutations of it, there will be no repetition. If no palindromic permutation is there, then simply return empty string.So, if the input is like "aabb", then the output will be ["abba", "baab"]To solve this, we will follow these steps −Define an array retDefine a function solve(), this will take s, sz, one unordered map m, idx initialize it with 0, if sz is same as 0, then −insert s at the end of retreturnevenFound := falseDefine one set visitedfor each key-value pair it of m, do −if ...
Read MoreHow to find the sum of two list elements in R?
The list elements of two lists cannot be added directly but we can do this addition by unlisting the elements. To do this, we would need to use lapply function. For example, if we have two lists defined as x and y then the sum of the elements in these lists can be calculated as follows:Examplelapply(seq_along(x), function(i) unlist(x[i])+unlist(y[i]))Example1> x1 x1Output[[1]] [1] 0 3 0 1 2 0 1 0 1 3 3 0 0 0 1 1 0 1 0 1 1 0 2 0 0 6 1 2 1 1 1 1 2 1 1 0 0 [38] 2 ...
Read MoreEncode and Decode Strings in C++
Suppose we have a list of strings. We have to design an algorithm that can encode the list of strings to a string. We also have to make one decoder that will decode back to the original list of strings. Suppose we have the encoder and decoder installed on these machines, and there are two different functions as follows −Machine 1 (sender) has the functionstring encode(vector
Read MoreHow to create a bar plot using ggplot2 with one bar having black border in R?
The bar plot can be easily created with the help of geom_bar. But if we want to have a different border for a particular bar then we first need to create the bar plot and store it in an object. After that we need to add the original plot with the bar for which we want to have a black border. Check out the below example to understand how it can be done.ExampleConsider the below data frame:> Group Freq df dfOutput Group Freq 1 G1 18 2 G2 27 3 G3 24Loading ggplot2 package ...
Read MoreFind the Celebrity in C++
Suppose we have n people (labeled from 0 to n - 1) and among them, there may exist one celebrity. We can say a person x is a celebrity when all the other n - 1 people know x but x does not know any of them. Here we have to find who the celebrity is or verify that there is not one.We are allowed to ask only one question to person ‘A’, that "Hi, A. Do you know B?" to get information of whether A knows B or not. We have to ask minimum number of questions tofind out ...
Read MoreHow to perform post hoc test for Kruskal-Wallis in R?
The Kruskal-Wallis test is the non-parametric analogue of one-way analysis of variance. The non-parametric tests are used in situations when the assumptions of parametric tests are not met. If we find significant difference in Kruskal-Wallis then post hoc tests are done to find where the difference exists. For this purpose, we can perform dunn test. The function of dunn test can be accessed through FSA package.Example1Loading FSA package:> library(FSA)Consider the below data frame:> x1 y1 df1 df1Output x1 y1 1 E 1.1191117 2 D 1.1276032 3 D 1.5610692 4 E 1.1585054 5 E 1.0239322 6 C 0.8000165 ...
Read MoreProgram to find nth ugly number in C++
Suppose we have a number n; we have to find the nth ugly number. As we know that the ugly numbers are those numbers, whose prime factors are only 2, 3 and 5. So if we want to find 10th ugly number, the output will be 12, as the first few ugly numbers are 1, 2, 3, 4, 5, 6, 8, 9, 10, 12 and so on.To solve this, we will follow these steps:Define an array v of size(n + 1)if n is same as 1, then:return 1two := 2, three := 3, five := 5twoIdx := 2, threeIdx := 2, fiveIdx := 2for initialize i := 2, when i
Read MoreHow to create an empty plot using ggplot2 in R?
The two most easy ways to create an empty plot using ggplot2 are using geom_blank function and also adding the theme_bw along with the geom_blank. The geom_blank will create an empty plot with white gridlines and grey background, on the other hand, addition of theme_bw will create the empty plot with grey gridlines and white background.ExampleConsider the below data frame:> set.seed(151) > x y df dfOutput x y 1 -0.05153895 0.3139643 2 0.76573738 0.1816184 3 -0.14673959 0.8201743 4 -0.11318581 1.6005576 5 -0.39551140 0.6770630 6 0.78227595 0.7446956 7 -1.39747811 0.7004385 8 -1.01883832 1.2728014 9 ...
Read MoreHow to find the mean of a square matrix elements by excluding diagonal elements in R?
There are many ways to find the mean of a matrix elements by excluding diagonal elements, this mean is actually the mean of lower triangular matrix and the upper triangular matrix. We can simply use mean function by creating a vector of lower and upper triangular matrix as shown in the below examples.Example1> M1 M1Output [, 1] [, 2] [, 3] [, 4] [1, ] 1 6 3 6 [2, ] 8 5 3 4 [3, ] 5 4 4 6 [4, ] 5 5 3 4 [5, ...
Read MoreZigzag Iterator in C++
Suppose there are two 1D arrays, we have to implement an iterator that will return their elements alternately. There will be two methods −next() − to get next elementhasNext() − to check whether the next element is present or not.So, if the input is like v1 = [1, 2] v2 = [3, 4, 5, 6] , then the output will be [1, 3, 2, 4, 5, 6], To solve this, we will follow these steps −Define one queue q of pairsFrom the initializer ake two arrays v1 and v2, if size of v1, then −insert { 0, 0 } into ...
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