Delta Karlsruhe Gewinnspiel

largest_prime_factor.go

package main

import (
	"fmt"
	"time"
)

func main() {
	N := int64(751395478255)
	n := N
	factor := int64(0)

	start := time.Now()

	for i := int64(2); i < n; i++ {
		for n%i == 0 {
			factor = i
			n = n / i
		}
	}

	if n > 1 {
		factor = n
	}

	fmt.Printf("Largest prime factor of %v is %v\n", N, factor)
	fmt.Printf("Execution time: %s\n", time.Since(start))
}