First N primes

Print the first N prime numbers.

Example

Input:

let N = 7

Expected value:

2
3
5
7
11
13
17

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Hint1

A number is prime if it has exactly 2 distinct divisors (1 and itself). You could simply check all potential divisors for each number and count the numbers with exactly 2 divisors.

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Hint2

Or you can learn about Eratosthene’s Sieve, which finds the prime numbers a lot faster.

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Solution

let N = 100
let maxP = 1000
var isPrime: [Bool] = []
var primes: [Int] = []
for i in 0...maxP {
    isPrime.append(true)
}
isPrime[0] = false
isPrime[1] = false
for i in 2...maxP {
    if isPrime[i] == true {
        var j = i*i
        while j <= maxP {
            isPrime[j] = false
            j += i
        }
        primes.append(i)
    }
}

for i in 0..<N {
    print(primes[i])
}

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