V* SearchRecursive(Node* node, K k)
{
if(node == nullptr)
return nullptr;
if(k == node->key)
return &node->value;
else if(k < node->key)
return SearchRecursive(node->left, k);
else
return SearchRecursive(node->right, k);
}
// Recursively searches the trie for queryword. previous row contains the edit distance for the string upto this trie node.
void SearchRecursive(struct Trie_Node *node, char *queryword, int *previous_row, int length) {
int current_row[length+1];
current_row[0] = previous_row[0]+1;
int min_current_row = current_row[0];
int ins_cost, del_cost, repl_cost;
int i;
// computes edit distance for this node.
for(i = 1; i <= length; i++) {
ins_cost = current_row[i-1]+1;
del_cost = previous_row[i]+1;
if(node->c == queryword[i-1])
repl_cost = previous_row[i-1];
else
repl_cost = previous_row[i-1]+1;
current_row[i] = minimum(ins_cost, del_cost, repl_cost);
if(min_current_row > current_row[i])
min_current_row = current_row[i];
}
if(node->is_word == 1 && current_row[length] < MIN_COST) {
MIN_COST = current_row[length];
}
// only if the min of current row is < MIN_COST, search further. This prunes the search.
if(min_current_row < MIN_COST) {
for(i = 0; i <= 25; i++) {
if(node->children[i] != NULL)
SearchRecursive(node->children[i], queryword, current_row, length);
}
}
}
// Search the trie from the root node
void SearchTrie(char *queryword) {
int length = strlen(queryword);
int current_row[length+1];
int i = 0;
for(i = 0; i <= length; i++) {
current_row[i] = i;
}
for(i = 0; i <= 25; i++) {
if(root->children[i] != NULL)
SearchRecursive(root->children[i], queryword, current_row, length);
}
}
