
Problem
Solution
Submissions
Generate the first n prime numbers.
Certification: Basic Level
Accuracy: 66.67%
Submissions: 6
Points: 5
Write a C# program to implement the GeneratePrimes(int n) function, which generates the first n prime numbers. A prime number is a natural number greater than 1 that is not divisible without a remainder by any natural number other than 1 and itself.
Algorithm
- Step 1: Start checking numbers from 2 (the first prime number).
- Step 2: For each number, check if it's prime by testing divisibility by all smaller primes.
- Step 3: If the number is prime, add it to the result list.
- Step 4: Continue until you have found n prime numbers.
Example 1
- Input: n = 5
- Output: [2, 3, 5, 7, 11]
- Explanation:
- The first prime number is 2.
- The second prime number is 3.
- The third prime number is 5.
- The fourth prime number is 7.
- The fifth prime number is 11.
Example 2
- Input: n = 10
- Output: [2, 3, 5, 7, 11, 13, 17, 19, 23, 29]
- Explanation:
- These are the first 10 prime numbers in ascending order.
Constraints
- 1 ≤ n ≤ 1000
- The function should return an array of the first n prime numbers
- Time Complexity: O(n * sqrt(n))
- Space Complexity: O(n)
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Solution Hints
- Use a combination of trial division and the fact that you only need to check divisibility by primes up to the square root of the number
- Keep track of the primes you've already found and use them for testing primality of subsequent numbers
- Consider using the Sieve of Eratosthenes algorithm for more efficient prime generation if you need to find many primes
- Remember that 2 is the only even prime number