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Articles on Trending Technologies
Technical articles with clear explanations and examples
Count Primes in Ranges in C++
We are given range variables START and END. The goal is to find the count of prime numbers in the range [START, END].We will check if number i in range is prime by checking if any number other than 1 fully divides it and is between 1 and i/2. If it is prime. Increment count.Let’s understand with examples.Input Start=1 End=20Output Primes in Ranges : 8Explanation Primes between 1 and 20 are: 2, 3, 5, 7, 11, 13, 17, 19.Input Start=100 End=200Output Primes in Ranges : 21Explanation Primes between 100 and 200 are: 101 103 107 109 113 127 131 137 139 149 151 157 163 167 ...
Read MoreCount quadruples from four sorted arrays whose sum is equal to a given value x in C++
We are given four arrays A[], B[], C[] and D[]. The goal is to find all quadruples of elements of these arrays such that A[i]+B[j]+C[k]+D[l] =x. All four arrays have the same number of elements N.We will do this by traversing each array once and compare if A[i]+B[j]+C[j]+D[l]==x. If true increment count.Let’s understand with examples.Input A[]={ 1, 2, 3}; B[]={ 2, 3, 2}; C[]={ 4, 3, 1}; D[]={ 3, 1, 1 }; X=12Output Count of Quadruples: 4Explanation Quadruples such as ( A[i] B[j] C[k] D[l] ) are: (2 3 4 3) , (3 2 4 3), (3 3 3 3), (3 2 4 ...
Read MoreCount numbers whose sum with x is equal to XOR with x in C++
We are a number X. The goal is to find numbers between 0 and X whose sum with X is equal to XOR with X.We will do this by traversing no. from i=0 to i
Read MoreCount numbers whose XOR with N is equal to OR with N in C++
We are a number N. The goal is to find numbers between 0 and N whose OR with N is equal to XOR with N.We will do this by traversing no. from i=0 to i
Read MoreWhat is the difference between $ and @ in R?
If we have a data frame defined as df that contains column x, y, and z then extraction of these columns from df can be done by using df$x, df$y, and df$z. On the other hand, if we have an S4 object defined as Data_S4 that contains column x, y, and z then the extraction of these columns can be done by using Data_S4@x, Data_S4@y, and Data_S4@z.Example of a data frame:Example> x1 x2 df dfOutput x1 x2 1 4 2 2 7 0 3 10 2 4 3 1 5 7 1 6 2 2 7 3 4 8 4 ...
Read MoreCount number of ways to divide a number in parts in C++
We are given a positive number N. The goal is to count the number of ways in which the number N can be divided into 3 parts. The parts may or may not be equal. N lies in range [1, 5000].We will do this by using three for loops for 3 parts of the number. Check at the innermost loop that the sum of all three is equal to N. If true, then increment the count of ways.Let’s understand with examples.Input − N=5Output − Number of ways to divide N in 3 parts: 2Explanation − 5 can be shown as ...
Read MoreHow to create a heatmap for lower triangular matrix in R?
A heatmap is a diagrammatic representation of data where the values are represented with colours. Mostly, it is used to display data that has slight variation. We can draw it for a full matrix, an upper triangular matrix as well as a lower triangular matrix. This can be done with the help of image function.Example1> M1 M1Output [, 1] [, 2] [, 3] [, 4] [, 5] [, 6] [1, ] 6 9 4 7 5 4 [2, ] 6 6 4 3 7 5 [3, ] 2 6 ...
Read MoreCount number of trailing zeros in product of array in C++
We are given an array Arr[] of positive integers of size N. The goal is to count the number of trailing zeroes present in the product of all elements of the array.We will do this by counting the factors of each number. We will count 2 and 5 as factors of each number as the product of 2 and 5 is 10 which gives 1 trailing 0. In the end whichever count is smaller gives the count of trailing zeroes in the product. If we have 4 2’s and 6 5’s then there will be 4 trailing zeroes in the ...
Read MoreCount numbers which can be represented as sum of same parity primes in C++
We are given an array Arr[] of positive integers of size N. The goal is to count the number of elements in that array which can be represented as sum of parity primes, that is they can be shown as a sum of the same prime number. Ex; 4= 2+2, 6=3+3 or 2+2+2The sum of any two odd or even prime numbers will always be even. And except 0 and 2 all even numbers can be represented as sum of same primes.Let’s understand with examples.Input Arr[] = { 2, 5, 10, 15, 20, 25 }Output Number which satisfy condition : 3Explanation Numbers as ...
Read MoreHow to extract the names of list elements in R?
The names of list elements can be extracted by using the names function. For example, if we have a list defined as List that contains three elements with names element1, element2, and element3 then then these names can be extracted from the List by using the below command:names(List)Example1> List1 List1Output$x1 [1] -0.04518909 -0.22779868 0.24339595 -0.86189295 -0.73387277 -0.75313131 [7] 0.39694608 2.30565359 0.55670193 0.21973762 0.62968128 -0.90936921 [13] 1.33946741 -0.16315751 0.31357793 0.40365980 -0.23639612 -2.48749453 [19] 0.52152768 -1.57059863 0.51728464 0.98177111 0.65475629 0.23715538 [25] -0.71796609 -0.42731839 0.32335282 -0.90013122 -0.84549927 -0.88358214 [31] -0.32066379 -0.98945433 0.42469849 -1.63095343 0.32584448 0.10947333 [37] 0.23486625 0.28166351 1.18432843 0.94828212 0.09452671 0.56618262 [43] ...
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