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ConsecutivePrimes.c
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ConsecutivePrimes.c
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#include <stdio.h>
static int count;
int isPrime(int number){
for(int i = 2;i<(int)(number/2)+1;i++){
if (number%i == 0) {
return 0;
}
}
return 1;
}
int isEven(int number)
{
if(number%2==0){
return 1;
}
return 0;
}
void calculateNumNecklacesC(int numOfBeads, int beadsArray[], int sizeBeadsArray, int necklace[], int sizeNecklaceArray)
{
if (sizeBeadsArray == 1) {
if((isPrime(necklace[sizeNecklaceArray-1] + beadsArray[sizeBeadsArray-1]) == 1) && (isPrime(necklace[0] + beadsArray[sizeBeadsArray-1])==1)){
necklace[sizeNecklaceArray+1] = beadsArray[sizeBeadsArray];
count +=1;
}
}else{
int previousNumber = necklace[sizeNecklaceArray-1];
int startPos = 0;
for (int pos = startPos; pos < sizeBeadsArray; pos++) {
if (isPrime(previousNumber + beadsArray[pos])) {
necklace[sizeNecklaceArray] = beadsArray[pos];
sizeNecklaceArray+=1;
int tempSizeBeadsArray = sizeBeadsArray-1;
int tempBeadsArray[tempSizeBeadsArray];
int tempPos = 0;
for (int i = 0; i<sizeBeadsArray; i++) {
if (i!=pos) {
tempBeadsArray[tempPos] = beadsArray[i];
tempPos+=1;
}
}
calculateNumNecklacesC(numOfBeads, tempBeadsArray, tempSizeBeadsArray, necklace, sizeNecklaceArray);
sizeNecklaceArray-=1;
}
}
}
}
int main(int argc, const char * argv[])
{
int input =18;
count = 0;
if (isEven(input)) {
int beadsArray[input-1];
int pos = 0;
while (pos<input-1) {
beadsArray[pos] = pos+2;
pos+=1;
}
int necklace[input];
necklace[0]=1;
calculateNumNecklacesC(input, beadsArray, input-1, necklace,1);
}
printf("answer: %d",count);
}