probleme_23.groovy

def dividorsOf(number) {
	def returned = new TreeSet()
	def max = Math.sqrt(number).longValue()+1L
	def range = max..1L
	for(factor in range) {
		if(!returned.contains(factor)) {
			if(number%factor==0) {
				if(factor<number)
					returned << factor
				def quotient = (number/factor).longValue()
				if(quotient<number)
					returned << quotient
			}
		}
	}
	return returned
}

def getAbundantsBelow(max) {
	def returned = new TreeSet()
	def dividors
	def dividorsSum
	for(number in 1L..max) {
		dividors = dividorsOf(number)
		dividorsSum = dividors.inject(0) { result, d -> result+d }
//		println "for $number, dividors are $dividors and their sum is $dividorsSum"
		if(dividorsSum>number) {
			returned << number
		}
	}
	return returned
}


def getNonSumsBelow(TreeSet abundants, max) {
	def returned = new TreeSet()
	for(number in 1L..max) {
	// small optimization to narrow search space
		usableOnes = abundants.headSet(number)
		iterator = usableOnes.iterator()
		def found = false
		// Good old Java loop allowing anything
		while(iterator.hasNext() && !found) {
			found = usableOnes.contains(number-iterator.next())
		}
		if(!found)
			returned << number
	}
	return returned
}

def MAX = 28123

long start = System.currentTimeMillis()
def abundants = getAbundantsBelow(MAX)
println "all abundants have been found, now searching non sums"
// now, find numbers that are not sums of abundant numbers
def nonSumOfAbundants = getNonSumsBelow(abundants, MAX)

println nonSumOfAbundants.inject(0L) {result, value -> result+value }

long end = System.currentTimeMillis();
println "duration "+((end-start)/1000.0)+" s";