Given an integer ‘n’, the task is to find the sum of first ‘n’ prime numbers.
First few prime numbers are: 2, 3, 5, 7, 11, 13, 17, 19, 23, ……
Input: N = 4 Output: 17 2, 3, 5, 7 are first 4 prime numbers so their sum is equal to 17 Input: N = 40 Output: 3087
- Create a sieve which will help us to identify if the number is prime or not in O(1) time.
- Run a loop starting from 1 until and unless we find n prime numbers.
- Add all the prime numbers and neglect those which are not prime.
- Then, display the sum of 1st N prime numbers.
Below is the implementation of the above solution
Sum of 1st N prime numbers are :17
Note(For competitive programming): In a problem which contains a large number of queries, a vector can be used to store all the prime numbers in the range of 10^8, this will take extra O(N) space. We can also use prefix array to store the sum of first N prime numbers in the range of 10^8.
- Absolute difference between the Product of Non-Prime numbers and Prime numbers of an Array
- Absolute difference between the XOR of Non-Prime numbers and Prime numbers of an Array
- Absolute Difference between the Sum of Non-Prime numbers and Prime numbers of an Array
- Print the nearest prime number formed by adding prime numbers to N
- Print prime numbers with prime sum of digits in an array
- Check if a prime number can be expressed as sum of two Prime Numbers
- Print numbers such that no two consecutive numbers are co-prime and every three consecutive numbers are co-prime
- Sum of prime numbers without odd prime digits
- Bitwise AND of the sum of prime numbers and the sum of composite numbers in an array
- Numbers less than N which are product of exactly two distinct prime numbers
- Print all numbers whose set of prime factors is a subset of the set of the prime factors of X
- Prime numbers after prime P with sum S
- Almost Prime Numbers
- Prime Numbers
- XOR of all Prime numbers in an Array
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to firstname.lastname@example.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.