Data commit

Task/Chernicks-Carmichael-numbers/Go/chernicks-carmichael-numbers-1.go

@@ -0,0 +1,57 @@
+package main
+
+import (
+    "fmt"
+    "math/big"
+)
+
+var (
+    zero = new(big.Int)
+    prod = new(big.Int)
+    fact = new(big.Int)
+)
+
+func ccFactors(n, m uint64) (*big.Int, bool) {
+    prod.SetUint64(6*m + 1)
+    if !prod.ProbablyPrime(0) {
+        return zero, false
+    }
+    fact.SetUint64(12*m + 1)
+    if !fact.ProbablyPrime(0) { // 100% accurate up to 2 ^ 64
+        return zero, false
+    }
+    prod.Mul(prod, fact)
+    for i := uint64(1); i <= n-2; i++ {
+        fact.SetUint64((1<<i)*9*m + 1)
+        if !fact.ProbablyPrime(0) {
+            return zero, false
+        }
+        prod.Mul(prod, fact)
+    }
+    return prod, true
+}
+
+func ccNumbers(start, end uint64) {
+    for n := start; n <= end; n++ {
+        m := uint64(1)
+        if n > 4 {
+            m = 1 << (n - 4)
+        }
+        for {
+            num, ok := ccFactors(n, m)
+            if ok {
+                fmt.Printf("a(%d) = %d\n", n, num)
+                break
+            }
+            if n <= 4 {
+                m++
+            } else {
+                m += 1 << (n - 4)
+            }
+        }
+    }
+}
+
+func main() {
+    ccNumbers(3, 9)
+}

Task/Chernicks-Carmichael-numbers/Go/chernicks-carmichael-numbers-2.go

@@ -0,0 +1,95 @@
+package main
+
+import (
+    "fmt"
+    big "github.com/ncw/gmp"
+)
+
+const (
+    min = 3
+    max = 10
+)
+
+var (
+    prod       = new(big.Int)
+    fact       = new(big.Int)
+    factors    = [max]uint64{}
+    bigFactors = [max]*big.Int{}
+)
+
+func init() {
+    for i := 0; i < max; i++ {
+        bigFactors[i] = big.NewInt(0)
+    }
+}
+
+func isPrimePretest(k uint64) bool {
+    if k%3 == 0 || k%5 == 0 || k%7 == 0 || k%11 == 0 ||
+        k%13 == 0 || k%17 == 0 || k%19 == 0 || k%23 == 0 {
+        return k <= 23
+    }
+    return true
+}
+
+func ccFactors(n, m uint64) bool {
+    if !isPrimePretest(6*m + 1) {
+        return false
+    }
+    if !isPrimePretest(12*m + 1) {
+        return false
+    }
+    factors[0] = 6*m + 1
+    factors[1] = 12*m + 1
+    t := 9 * m
+    for i := uint64(1); i <= n-2; i++ {
+        tt := (t << i) + 1
+        if !isPrimePretest(tt) {
+            return false
+        }
+        factors[i+1] = tt
+    }
+
+    for i := 0; i < int(n); i++ {
+        fact.SetUint64(factors[i])
+        if !fact.ProbablyPrime(0) {
+            return false
+        }
+        bigFactors[i].Set(fact)
+    }
+    return true
+}
+
+func prodFactors(n uint64) *big.Int {
+    prod.Set(bigFactors[0])
+    for i := 1; i < int(n); i++ {
+        prod.Mul(prod, bigFactors[i])
+    }
+    return prod
+}
+
+func ccNumbers(start, end uint64) {
+    for n := start; n <= end; n++ {
+        mult := uint64(1)
+        if n > 4 {
+            mult = 1 << (n - 4)
+        }
+        if n > 5 {
+            mult *= 5
+        }
+        m := mult
+        for {
+            if ccFactors(n, m) {
+                num := prodFactors(n)
+                fmt.Printf("a(%d) = %d\n", n, num)
+                fmt.Printf("m(%d) = %d\n", n, m)
+                fmt.Println("Factors:", factors[:n], "\n")
+                break
+            }
+            m += mult
+        }
+    }
+}
+
+func main() {
+    ccNumbers(min, max)
+}