func ncat(n []uint64) uint64 {
var rd []uint64
for i := len(n) - 1; i >= 0; i-- {
rd = append(rd, euler.NtoD(n[i])...)
}
return euler.DtoN(rd)
}
func main() {
var sum uint64
digits := euler.NtoD(9876543210)
firstprimes := []uint64{2, 3, 5, 7, 11, 13, 17}
numperms := euler.Factorial(uint64(len(digits)))
search:
for j := uint64(0); j < numperms; j++ {
d := euler.NthPerm(j, digits)
for i := range firstprimes {
if euler.DtoN(d[i+1:i+4])%firstprimes[i] != 0 {
continue search
}
}
sum += euler.DtoN(d)
}
fmt.Printf("43 %d\n", sum)
}
func main() {
var total uint64
nf := euler.Factorial(9)
uniq := make(map[uint64]bool)
for i := uint64(0); i < nf; i++ {
p := euler.NthPerm(i, []uint64{1, 2, 3, 4, 5, 6, 7, 8, 9})
for j := 1; j < 5; j++ {
a, b, c := euler.DtoN(p[:j]), euler.DtoN(p[j:5]), euler.DtoN(p[5:])
if a*b == c {
uniq[c] = true
}
}
}
for i := range uniq {
total += i
}
fmt.Printf("32 %d\n", total)
}
func main() {
var count uint64
var sum uint64
nextcandidate:
for i := uint64(11); count < 11; i++ {
d := euler.NtoD(i)
dlen := len(d)
for j := 0; j < len(d); j++ {
a := euler.DtoN(d[j:dlen])
b := euler.DtoN(d[0 : dlen-j])
if !euler.IsPrime(a) || !euler.IsPrime(b) {
continue nextcandidate
}
}
count++
sum += i
}
fmt.Printf("%d\n", sum)
}
func main() {
var largest uint64
digits := []uint64{1, 2, 3, 4, 5, 6, 7, 8, 9}
for i := uint64(1); i <= 9; i++ {
numperms := euler.Factorial(i)
for j := uint64(0); j < numperms; j++ {
dn := euler.NthPerm(j, digits[:i])
n := euler.DtoN(dn)
if euler.IsPrime(n) && pandigital(n) {
if n > largest {
largest = n
}
}
}
}
fmt.Printf("41 %d\n", largest)
}
func rot(n uint64) (uint64, bool) {
d := euler.NtoD(n)
d = append(d[len(d):], d[:len(d)]...)
return euler.DtoN(d), d[0] > 0
}