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WordFilter.java
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WordFilter.java
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package g0701_0800.s0745_prefix_and_suffix_search;
// #Hard #String #Design #Trie #Udemy_Trie_and_Heap
// #2022_03_25_Time_366_ms_(76.15%)_Space_262.7_MB_(32.80%)
public class WordFilter {
private static class TrieNode {
TrieNode[] children;
int weight;
TrieNode() {
this.children = new TrieNode[27];
this.weight = 0;
}
}
private TrieNode root = new TrieNode();
public WordFilter(String[] words) {
for (int i = 0; i < words.length; i++) {
String s = words[i];
for (int j = 0; j < s.length(); j++) {
insert(s.substring(j) + '{' + s, i);
}
}
}
public void insert(String wd, int weight) {
TrieNode node = root;
for (char ch : wd.toCharArray()) {
if (node.children[ch - 'a'] == null) {
node.children[ch - 'a'] = new TrieNode();
}
node = node.children[ch - 'a'];
node.weight = weight;
}
}
public int f(String prefix, String suffix) {
return startsWith(suffix + '{' + prefix);
}
public int startsWith(String pref) {
TrieNode node = root;
for (char ch : pref.toCharArray()) {
if (node.children[ch - 'a'] == null) {
return -1;
}
node = node.children[ch - 'a'];
}
return node.weight;
}
}