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Programming Articles
Page 1245 of 2547
Binary 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 >= ...
Read MoreHow to create smooth density curves without filling densities in R?
The density curves can be created by using stat_density function of ggplot2 package but it fills the curve with density hence it becomes difficult to recognize the curves. We can remove these densities by using geom="line" inside the stat_density function so that only the density curves will be plotted.ExampleConsider the below data frame:> G Response df dfOutputG Response 1 C 1.0229016 2 C 1.0058160 3 B 0.8831558 4 B 0.7729167 5 C 0.9130468 6 D 0.8431893 7 B 1.5003581 8 A 0.9687335 9 B 1.1139661 10 A 0.9211660 11 A 1.1790619 12 D 0.6349671 13 A 1.2616918 14 A 1.6021078 ...
Read MoreHow to subset rows of an R data frame using grepl function?
The grepl function in R search for matches to argument pattern within each element of a character vector or column of an R data frame. If we want to subset rows of an R data frame using grepl then subsetting with single-square brackets and grepl can be used by accessing the column that contains character values.Example1Consider the below data frame:> x1 y1 z1 df1 df1Output x1 y1 z1 1 A 0.8833979 5 2 B 0.5400075 1 3 C 0.6923827 3 4 B 1.5069186 2 5 B 0.8190962 2 6 B 0.8296171 1 7 B ...
Read MoreCount numbers having 0 as a digit in C++
We are provided a number N. The goal is to find the numbers that have 0 as digit and are in the range [1, N].We will do this by traversing numbers from 10 to N ( no need to check from 1 to 9 ) and for each number we will check each digit using a while loop. If any digit is found as zero increment count and move to next number otherwise reduce the number by 10 to check digits until number is >0.Let’s understand with examples.Input N=11Output Numbers from 1 to N with 0 as digit: 1Explanation Starting from i=10 to ...
Read MoreNumber of Connected Components in an Undirected Graph in C++
Suppose we have n nodes and they are labeled from 0 to n - 1 and a list of undirected edges, are also given, we have to define one function to find the number of connected components in an undirected graph.So, if the input is like n = 5 and edges = [[0, 1], [1, 2], [3, 4]], then the output will be 2To solve this, we will follow these steps −Define a function dfs(), this will take node, graph, an array called visited, if visited[node] is false, then −visited[node] := truefor initialize i := 0, when i < size ...
Read MoreHow to find the group-wise correlation coefficient in R?
If we have two continuous and one categorical column in an R data frame then we can find the correlation coefficient between continuous values for the categories in the categorical column. For this purpose, we can use by function and pass the cor function with the spearman method as shown in the below examples.Example1Consider the below data frame:> x1 y1 z1 df1 df1Output x1 y1 z1 1 A 1.1155324 2 2 C 0.9801564 3 3 B 0.9116162 1 4 A 0.8406772 3 5 C 0.8009355 2 6 A 0.9331637 2 7 B 1.0642089 1 ...
Read MoreCount numbers in a range that are divisible by all array elements in C++
We are provided two numbers START and END to define a range of numbers. And also an array of positive numbers Arr[]. The goal is to find all the numbers that are divisible by all elements of Arr[] and are in the range [START, END] .Method 1 ( Naive Approach )We will do this by traversing numbers from START to END and for each number we will check if the number is divisible by all elements of the array. If yes increment count.Method 2 ( check divisibility by LCM of array elements )We will find the LCM of all array ...
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