gistfile1.go

// Euler Project
// Problem 45: https://projecteuler.net/problem=45

package main

import (
	"fmt"
)

func main() {
	var p, h int

	pen := seq(func(i int) int { return i * (3 * i - 1) / 2}, 165)
	hex := seq(func(i int) int  { return i * (2 * i - 1)}, 144)

	func() {
		h = <-hex
		for ;; p = <-pen {
			if h == p {
				return
			}
			if p > h {
				h = <-hex
			}
		}
	}()
	fmt.Println(h)
}

func seq(fn func(int) int, beg int) <-chan int {
	c := make(chan int)
	go func() {
		for i := beg; ; i++ {
			c <- fn(i)
		}
	}()
	return c
}