net.automatalib.util.tries.SharedSuffixTrie Maven / Gradle / Ivy
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This artifact provides various common utility operations for analyzing and manipulating
automata and graphs, such as traversal, minimization and copying.
/* Copyright (C) 2013-2019 TU Dortmund
* This file is part of AutomataLib, http://www.automatalib.net/.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package net.automatalib.util.tries;
import net.automatalib.words.Alphabet;
public class SharedSuffixTrie extends SuffixTrie {
private final Alphabet alphabet;
public SharedSuffixTrie(Alphabet alphabet) {
super(new SharedSuffixTrieNode<>());
this.alphabet = alphabet;
}
public SharedSuffixTrie(Alphabet alphabet, boolean graphRepresentable) {
super(graphRepresentable, new SharedSuffixTrieNode<>());
this.alphabet = alphabet;
}
@Override
@SuppressWarnings("unchecked")
public SuffixTrieNode add(I symbol, SuffixTrieNode parent) {
if (!(parent instanceof SharedSuffixTrieNode)) {
throw new IllegalArgumentException("Invalid suffix trie node");
}
int symbolIdx = alphabet.getSymbolIndex(symbol);
SharedSuffixTrieNode sparent = (SharedSuffixTrieNode) parent;
SharedSuffixTrieNode[] children = sparent.children;
if (children == null) {
sparent.children = new SharedSuffixTrieNode[alphabet.size()];
children = sparent.children;
} else if (children[symbolIdx] != null) {
return children[symbolIdx];
}
SharedSuffixTrieNode child = new SharedSuffixTrieNode<>(symbol, sparent);
children[symbolIdx] = child;
return child;
}
}