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August 24, 2014 09:43
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| package main | |
| // Euler Project #50: http://projecteuler.net/problem=50 | |
| import ( | |
| "fmt" | |
| "math" | |
| "runtime" | |
| ) | |
| func main() { | |
| fmt.Printf("Number of CPUs: %d\n", runtime.NumCPU()) | |
| runtime.GOMAXPROCS(runtime.NumCPU()) | |
| primes := getPrimes(1000000) | |
| fmt.Println("... ", primes[len(primes) - 10:]) | |
| l := len(primes) - 1 | |
| ch := make(chan []int) | |
| ch2 := make(chan int) | |
| for i := l; i >= 0; i-- { | |
| go checkPrime(i, l, primes , ch, ch2) | |
| } | |
| var max int | |
| var num int = 0 | |
| var a, answer []int | |
| Loop: | |
| for { | |
| select { | |
| case <- ch2: { | |
| num++ | |
| if num >= l { | |
| break Loop | |
| } | |
| } | |
| case a = <- ch: { | |
| if a[0] > max { | |
| answer = a | |
| max = a[0] | |
| } | |
| } | |
| } | |
| } | |
| fmt.Println(answer) | |
| } | |
| func checkPrime(i, l int, primes []int, ch chan []int, ch2 chan int) { | |
| var sum int = 0 | |
| for j := 0; j <= l; j++ { | |
| sum = 0 | |
| for k := j; k <= l; k++ { | |
| sum += primes[k] | |
| if sum > primes[i] { | |
| break | |
| } | |
| if sum == primes[i] { | |
| ch <- []int{k -j, sum} | |
| } | |
| } | |
| } | |
| ch2 <- 1 | |
| } | |
| func getPrimes(n int) []int { | |
| var primeList = []int{2} | |
| var isPrime bool = true | |
| var num int = 3 | |
| var sqrtNum int = 0 | |
| for num < n { | |
| sqrtNum = int(math.Sqrt(float64(num))) | |
| for i := 0; i < len(primeList); i++ { | |
| if num % primeList[i] == 0 { | |
| isPrime = false | |
| } | |
| if primeList[i] > sqrtNum { | |
| i = len(primeList) | |
| } | |
| } | |
| if isPrime { | |
| primeList = append(primeList, num) | |
| } else { | |
| isPrime = true | |
| } | |
| num = num + 2 | |
| } | |
| return primeList | |
| } |
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