//rehash element from one table to another
//Arguments: h- old table, newhash - new table, oldCode - index of the element in old table ( h )
int reHash(HashTable *h, HashTable *newHash, int oldCode){
int oldPrefix = findPrefixGivenCode(h,oldCode); //store values to avoid recalculation
int oldChar = findCharGivenCode(h,oldCode);
bool isRehashed = findisRehashedGivenCode(h,oldCode);
if (oldChar == -1){ //if empty slot return -1
return -1;
}
else if(isRehashed){ //if already rehashed slot, return prefix
return oldPrefix;
}
else if (oldPrefix == emptyCode){ //if prefix is 0
((*h)[oldCode]).isRehashed = 1; //re-insert it
int t = insertInHashTable(newHash,oldPrefix,oldChar);
((*h)[oldCode]).prefix = t;
return ((*h)[oldCode]).prefix; //return prefix where inserted
}
else{
int k = reHash(h,newHash,oldPrefix); //recursive case
int m = insertInHashTable(newHash,k,oldChar); //unfold prefixes and insert when hit 0
((*h)[oldCode]).prefix = m;
((*h)[oldCode]).isRehashed = 1;
return m;
}
return -1;
}
long memo_coin_sums(int* dens, int size, int amount, HashTable *memo) {
Tuple* tuple = convert_to_tuple(dens, size, amount);
if(inHashTable(tuple, memo)) {
return getFromHashTable(memo, tuple);
}
else {
if(amount<0) return 0;
else if(amount==0) return 1;
else if(size==1) {
if(amount%dens[0]==0) return 1;
else return 0;
}
else {
long result = memo_coin_sums(dens, size-1, amount, memo) + memo_coin_sums(dens, size, amount-dens[size-1], memo);
insertInHashTable(memo, tuple, result);
return result;
}
}
}
//add default ascii character to hash table h
void addDefault(HashTable *h){
for (int i = 0 ; i < 256 ; i++ ){ //insert ascii codes
insertInHashTable(h,0,i);
}
}
