https://projecteuler.net/problem=14

euler14.go

package main

import "fmt"

func main() {
	terms := make([]int16, 1000001)

	maxterms := int16(0)
	maxtermsNum := 0
	for i := range terms {
		c := int64(i)
		count := int16(1)
		for c > 1 {
			if c%2 == 0 {
				c = c / 2
			} else {
				c = c*3 + 1
			}

			if c < int64(i) {
				count = count + terms[c]
				break
			}
			count++
		}
		terms[i] = count
		if count > maxterms {
			maxterms = count
			maxtermsNum = i
		}
	}
	fmt.Println(maxtermsNum, maxterms)
}