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| #include <bits/stdc++.h>
using namespace std;
#define INF 1<<30
#define MAX 100005
#define FASTIO ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);
typedef long long ll;
const int ALPHABET = 26;
#define scale(x) (x - 'a')
struct TrieTree
{
struct TrieTree *children[ALPHABET];
bool isEndOfWord;
};
struct TrieTree *getNode()
{
struct TrieTree *Node = new TrieTree;
Node->isEndOfWord = false;
for(int i = 0; i < ALPHABET; i++)
Node->children[i] = NULL;
return Node;
}
void insert(struct TrieTree *root, string s)
{
struct TrieTree *curr = root;
for(int i = 0; i < s.size(); i++){
int idx = scale(s[i]);
if(!curr->children[idx])
curr->children[idx] = getNode();
curr = curr->children[idx];
}
// mark last node as leaf
curr->isEndOfWord = true;
}
bool search(struct TrieTree *root, string s)
{
struct TrieTree *curr = root;
for(int i = 0; i < s.size(); i++){
int idx = scale(s[i]);
if(!curr->children[idx])
return false;
curr = curr->children[idx];
}
return (curr != NULL && curr ->isEndOfWord);
}
bool isEmpty(TrieTree* root)
{
for(int i = 0; i < ALPHABET; i++)
if(root->children[i])
return false;
return true;
}
TrieTree* Remove(TrieTree* root, string s, int depth = 0)
{
if(!root)return NULL;
if(depth == s.size()){
if(root->isEndOfWord)
root->isEndOfWord = false;
if(isEmpty(root)){
delete(root);
root = NULL;
}
return root;
}
int idx = scale(s[depth]);
root->children[idx] = Remove(root->children[idx], s, depth+1);
if(isEmpty(root) && root->isEndOfWord == false){
delete(root);
root = NULL;
}
return root;
}
int main()
{
//FASTIO
/*//
//double start_time = clock();
#ifndef ONLINE_JUDGE
freopen("in.txt", "r", stdin);
freopen("out.txt", "w", stdout);
freopen("error.txt", "w", stderr);
#endif
//*/
string str[] = { "the", "a", "there",
"answer", "any", "by",
"bye", "their", "hero", "heroplane"};
int n = sizeof(str)/sizeof(str[0]);
struct TrieTree *root = getNode();
for(int i = 0; i < n; i++)
insert(root, str[i]);
// Search for different keys
search(root, "the")? cout << "FOUND!\n" : cout << "NOT FOUND\n";
search(root, "these")? cout << "FOUND!\n" : cout << "NOT FOUND\n";
Remove(root, "heroplane");
// Remove(root, "hero");
search(root, "hero") ? cout << "FOUND!\n" : cout << "NOT FOUND\n";
//double end_time = clock();
//printf( "Time = %lf ms\n", ( (end_time - start_time) / CLOCKS_PER_SEC)*1000);
return 0;
}
|
