Article Categories
- All Categories
-
Data Structure
-
Networking
-
RDBMS
-
Operating System
-
Java
-
MS Excel
-
iOS
-
HTML
-
CSS
-
Android
-
Python
-
C Programming
-
C++
-
C#
-
MongoDB
-
MySQL
-
Javascript
-
PHP
-
Economics & Finance
Articles on Trending Technologies
Technical articles with clear explanations and examples
Program to find longest path between two nodes of a tree in Python
Suppose we have a binary tree; we have to find the longest path between any two nodes in the tree.So, if the input is like then the output will be 5 To solve this, we will follow these steps:ans := 0Define a function getMaxPath() . This will take nodeif node is null, thenreturn 0leftCnt := getMaxPath(left of node)rightCnt := getMaxPath(right of node)temp := 1 + maximum of leftCnt and rightCntans := maximum of ans and l+r+1From the main method do the following −getMaxPath(root)return ansLet us see the following implementation to get better understanding −Exampleclass TreeNode: def __init__(self, val, left=None, right=None): ...
Read MoreHow to create a point chart with empty points using ggplot2 in R?
The point chart can be created by using geom_point function and if we want to create a point chart for single vector then we should pass the vector in both the places inside aes function. Also, by default the points are complete black circles and if we want to change the points to empty points then shape argument can be used.ExampleConsider the below data frame −set.seed(171) x
Read MoreHow to generate a power sequence of two in R?
In R, for the calculation of power we can simply use power operator ^ and this will be also used in case of generating a power sequence. For example, if we want to generate a power sequence from 1 to 5 of 2 then we can use the code 2^(1:5) this will result 2 4 8 16 32.Example2^(0:2)Output[1] 1 2 4Example2^(0:10)Output[1] 1 2 4 8 16 32 64 128 256 512 1024 Example2^(0:50)Output[1] 1.000000e+00 2.000000e+00 4.000000e+00 8.000000e+00 1.600000e+01 [6] 3.200000e+01 6.400000e+01 1.280000e+02 2.560000e+02 5.120000e+02 [11] 1.024000e+03 2.048000e+03 4.096000e+03 8.192000e+03 1.638400e+04 [16] 3.276800e+04 6.553600e+04 1.310720e+05 2.621440e+05 5.242880e+05 [21] 1.048576e+06 2.097152e+06 4.194304e+06 ...
Read MoreHow to find p-value for correlation coefficient in R?
The t test is used to find the p−value for the correlation coefficient and on the basis of that we decide whether there exists a statistically significant relationship between two variables or not. In R, we can perform this test by using function cor.test. For example, if we have a vector x and y then we can find the p−value using cor.test(x,y).Example1set.seed(444) x1
Read MoreHow to convert factor levels into character in R?
To convert factor levels into character then we can use as.character function by accessing the column of the data frame that contain factor values. For example, if we have a data frame df which contains a factor column named as Gender then this column can be converted into character column as as.character(df$Gender).Exampley1
Read MoreHow to combine array of vectors in R?
To combine array of vectors we can use rbind function. For example, if we have multiple vectors say x, y, z of same size or different sizes but the total number of elements are even then we can use rbind(x,y,z) to combine those vectors. Check out the examples to understand how it works.Example1x1
Read MoreHow to create a regression model in R with interaction between all combinations of two variables?
The easiest way to create a regression model with interactions is inputting the variables with multiplication sign that is * but this will create many other combinations that are of higher order. If we want to create the interaction of two variables combinations then power operator can be used as shown in the below examples.Example1x1
Read MoreHow to convert a vector into data frame in R?
If we want to convert an object into a data frame then as.data.frame function can be used, we just need to read the object that we want to convert with as.data.frame. For example, if we have a vector x then it can be converted to data frame by using as.data.frame(x) and this can be done for a matrix as well.Example1x
Read MoreHow to add named vectors of different sizes based on names in R?
If we have named vectors but the names come from same family then they cannot be added to each other direct to get the sum of values based on names. To do this, we need to use tapply function. For example, if we have three vectors defined as x, y, and z then firstly they need to be combined as V
Read MoreHow to calculate two period moving average for vector elements in R?
If we want to find the two−period moving average easily then it cannot be done in base R. We need to use rollmean function of zoo package that solves this problem in a single line of code. For example, if we have a vector x that contains hundred from starting from 1 to 100 then the two−period moving for x can be found by using rollmean(x,2)Loading zoo package −library(zoo)Examplesx1
Read More