Problem #7

Problem link
Solution:

package main

func main() {
    arr := make([]bool, 105000)
    arr[0], arr[1] = true, true
    count, prime := 2, 3
    var k int
    for {
        for k = 2 * prime; k < len(arr); k += prime {
            arr[k] = true
        }
        for k = prime + 2; k < len(arr) && arr[k]; k += 2 {
        }
        if k < len(arr) {
            prime = k
            count++
            if count == 10001 {
                println(prime)
                break
            }
        } else {
            break
        }
    }
}

After learning that the result is 104743, size of the boolean array is dropped down to 105000

Result: 104743
Time: 0m0.006s