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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to create a replicated list of a list in R?
Sometimes we want to created repeated values, this is helpful in different scenarios such as measuring an effect of a constant on multiple variables. The list values can be also replicated for similar purpose of analysis. The replication of list of a list can be created by using rep function. For example, if we have a list called x and we want to create five times replicated list of this list then we can use the code rep(list(x), 5).Example1> List1 List1Output$x1 [1] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 ...
Read MoreFlip Game II in C++
Suppose there are two players who are playing the flip game. Here we have a string that contains only these two characters: + and -, player1 and player2 take turns to flip two consecutive "++" into "--". The game ends when one player can no longer make a move and therefore the other one will be the winner. We have to define a function to check whether the starting player can guarantee a win.So, if the input is like s = "++++", then the output will be true, as the starting player can guarantee a win by flipping the middle ...
Read MoreBinary Tree Longest Consecutive Sequence in C++
Suppose we have a binary tree; we have to check whether we can find the length of the longest consecutive sequence path. If the path refers to any sequence of nodes from some starting node to any node in the tree along the parent-child connections. The longest consecutive path need to follow parent to child but not reverse.So, if the input is like, then the output will be 3, as the Longest consecutive sequence path is 3-4-5, so return 3.To solve this, we will follow these steps −Define a function solveUtil(), this will take node, prev, len initialize it with ...
Read MoreHow to find the column means of a column based on another column values that represent factor in an R data frame?
If we have a column that represent factor then we might want to find the mean of values in other column(s) for the factor levels. This is helpful in comparing the levels of the factor. In R, we can find the mean for such type of data by using aggregate function. Check out the below examples to understand how it can be done.Example1Consider the below data frame:> x1 y1 df1 df1Output x1 y1 1 D 5.801197 2 B 3.432060 3 B 6.154168 4 A 5.466655 5 D 5.171689 6 C 5.175170 7 B 5.353469 8 D 4.840470 ...
Read MoreHow to convert a date or date vector to POSIXct in R?
To convert a date or date vector to POSIXct, we can use as.POSIXct function but we also need to pass the appropriate date format inside the function. For example, if we have a date "2020-11-14" then it can be converted to POSIXct by using as.POSIXct("2020-11-14", format="%Y-%m-%d").Example1> date1 as.POSIXct(date1, format="%Y-%m-%d")Output[1] "2020-04-01 IST"Example2> date2 date2Output[1] "2020-02-12" "2020-06-01" "2020-04-01" "2020-05-01" "2020-01-21" [6] "2020-01-21" "2020-06-01" "2020-04-27" "2020-05-11" "2020-06-01" [11] "2020-01-21" "2020-03-31" "2020-05-01" "2020-02-12" "2020-01-21" [16] "2020-05-01" "2020-03-31" "2020-04-01" "2020-05-01" "2020-01-21" [21] "2020-05-01" "2020-04-11" "2020-05-11" "2020-04-01" "2020-03-31" [26] "2020-04-11" "2020-04-01" "2020-03-31" "2020-04-01" "2020-04-11" [31] "2020-05-11" "2020-06-01" "2020-03-31" "2020-04-27" "2020-01-21" [36] "2020-01-21" "2020-04-01" "2020-06-01" "2020-05-01" "2020-10-01" ...
Read MoreCount number of triplets with product equal to given number in C++
We are given an array Arr[] of integers with length n and a number M. The array is only containing positive integers. The goal is to count the triplets of elements of Arr[] which have product equal to M.We will do this by using three for loops. Increment count if arr[x]*arr[y]*arr[z]=M and x!=y!=z. (0
Read MoreBinary Tree Vertical Order Traversal in C++
Suppose there is a binary tree, we have to find the vertical order traversal of its nodes' values. If two nodes are in the same row and column, the order should be from left to right.So, if the input is like, then the output will be [[9], [3, 15], [20], [7]]To solve this, we will follow these steps −Define one map mDefine a function solve(), this will take node, x initialize it with 0, if node is null, then −returnsolve(left of node, x - 1)solve(right of node, x + 1)insert value of node at the end of m[x]From the main ...
Read MoreHow to check if some specific columns of an R data frame are equal to a column or not?
If we have a large amount of data in a data frame and we suspect that some of the data columns are repeated or some of them are equal to a particular column then we can use sapply function in base R to figure it out. In this way, we can remove duplicated columns that does not suppose to help in our data analysis objective.Example1Consider the below data frame:> set.seed(354) > x1 x2 x3 x4 x5 df1 df1Outputx1 x2 x3 x4 x5 1 4 5 4 4 6 2 6 4 8 7 5 3 5 6 4 7 6 ...
Read MoreCount numbers from range whose prime factors are only 2 and 3 in C++
We are provided two numbers START and END to define a range of numbers. The goal is to find the numbers that have only 2 and 3 as their prime factors and are in the range [START, END].We will do this by traversing numbers from START to END and for each number we will check if the number is divisible by 2 and 3 only. If divisible, divide it and reduce it. If not, break the loop. In the end if the number is reduced to 1 then it has only 2 and 3 as its factors.Let’s understand with examples.Input START=20 ...
Read MoreGeneralized Abbreviation in C++
Suppose there is a word. We have to define a function that can generate the generalized abbreviations of a word.So, if the input is like "word", then the output will be ["word", "1ord", "w1rd", "wo1d", "wor1", "2rd", "w2d", "wo2", "1o1d", "1or1", "w1r1", "1o2", "2r1", "3d", "w3", "4"]To solve this, we will follow these steps −Define an array retDefine a function solve(), this will take s, idx, if idx >= size of s, then −insert s at the end of retreturny := substring of s from index 0 to idx - 1i := size of ynum := blank stringwhile (i >= ...
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