Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
Count 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+2
The 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 : 3
Explanation
Numbers as sum of same primes: Arr[0] = 2 X count=0 Arr[1] = 5 : X count=0 Arr[2] = 10 :5+5 count=1 Arr[3] = 15 : X count=1 Arr[4] = 20 : 5+5+5+5 count=2 Arr[5] = 25 : X count=2
Input
Arr[] = { 0, 2, 4, 11, 13}Output
Number which satisfy condition : 1
Explanation
Numbers as sum of same primes: Arr[0] = 0 : X count=0 Arr[1] = 2 : X count=0 Arr[2] = 4 : 2+2 count=1 Arr[3] = 11 : X count=1 Arr[4] = 13 : X count=1
Approach used in the below program is as follows
We take an array of positive integers of length N..
Function sumofparityPrimes(int arr[],int n) takes array and n as input and returns the number of elements that can be represented as sum of parity primes.
Take the initial variable count as 0 for such numbers..
Traverse array using for loop.
For each element if it is even ( arr[i]%2==0 ).
Then check it is neither 0 nor 2. If true increment count.
Return the count as result at the end of for loop.
Example
#include <bits/stdc++.h>
using namespace std;
int sumofparityPrimes(int arr[],int n){
int count = 0;
for(int i=0;i<n;i++){
if(arr[i]%2==0) //num is even only{
if(arr[i]!=0){
if(arr[i]!=2)
{ count++; } //neither 0 nor 2
}
}
}
return count;
}
int main(){
int Arr[]={ 12, 5 , 15, 8, 100, 40 };
int Length= sizeof(Arr)/sizeof(Arr[0]);
cout <<endl<< "Number which satisfy condition : "<<sumofparityPrimes(Arr,Length);
return 0;
}Output
If we run the above code it will generate the following output −
Number which satisfy condition : 4
100 Views
To Continue Learning Please Login