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Copy pathSolution.java
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131 lines (104 loc) · 3.88 KB
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import java.io.File;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Scanner;
import java.util.stream.Collectors;
public class Solution {
static final String DICTIONARY_FILE_PATH = "dictionary.lst";
public static void main(String[] args) throws Throwable {
List<String> dictionary = readDictionary();
List<String> cipherWords = readCiphertext();
Map<Character, Character> decodeMap = new HashMap<Character, Character>();
decode(dictionary, cipherWords, decodeMap);
System.out.println(String.join(" ", cipherWords.stream().map(cipherWord -> decodeWord(decodeMap, cipherWord))
.collect(Collectors.toList())));
}
static boolean decode(List<String> dictionary, List<String> cipherWords, Map<Character, Character> decodeMap) {
boolean allDone = true;
String chosenCipherWord = null;
List<String> chosenMatchedDictionary = null;
for (String cipherWord : cipherWords) {
if (!isAllMapped(cipherWord, decodeMap)) {
allDone = false;
List<String> matchedDictionary = match(cipherWord, dictionary, decodeMap);
if (chosenMatchedDictionary == null || matchedDictionary.size() < chosenMatchedDictionary.size()) {
chosenCipherWord = cipherWord;
chosenMatchedDictionary = matchedDictionary;
}
}
}
if (allDone) {
return true;
}
if (chosenMatchedDictionary.isEmpty()) {
return false;
}
for (String chosenMatchedDictionaryWord : chosenMatchedDictionary) {
Map<Character, Character> addedDecodeMap = buildAddedDecodeMap(chosenCipherWord,
chosenMatchedDictionaryWord, decodeMap);
decodeMap.putAll(addedDecodeMap);
if (decode(dictionary, cipherWords, decodeMap)) {
return true;
}
for (char addedKey : addedDecodeMap.keySet()) {
decodeMap.remove(addedKey);
}
}
return false;
}
static List<String> match(String cipherWord, List<String> dictionary, Map<Character, Character> decodeMap) {
return dictionary.stream().filter(dictionaryWord -> isMapped(cipherWord, dictionaryWord, decodeMap))
.collect(Collectors.toList());
}
static boolean isMapped(String cipherWord, String dictionaryWord, Map<Character, Character> decodeMap) {
if (cipherWord.length() != dictionaryWord.length()) {
return false;
}
for (int i = 0; i < cipherWord.length(); i++) {
char cipherLetter = cipherWord.charAt(i);
if (decodeMap.containsKey(cipherLetter) && decodeMap.get(cipherLetter) != dictionaryWord.charAt(i)) {
return false;
}
}
return true;
}
static Map<Character, Character> buildAddedDecodeMap(String cipherWord, String dictionaryWord,
Map<Character, Character> decodeMap) {
Map<Character, Character> addedDecodeMap = new HashMap<Character, Character>();
for (int i = 0; i < cipherWord.length(); i++) {
char cipherLetter = cipherWord.charAt(i);
if (decodeMap.containsKey(cipherLetter)) {
continue;
}
addedDecodeMap.put(cipherLetter, dictionaryWord.charAt(i));
}
return addedDecodeMap;
}
static boolean isAllMapped(String cipherWord, Map<Character, Character> decodeMap) {
return cipherWord.chars().allMatch(letter -> decodeMap.containsKey((char) letter));
}
static String decodeWord(Map<Character, Character> decodeMap, String cipherWord) {
return cipherWord.chars().mapToObj(cipherLetter -> decodeMap.get((char) cipherLetter))
.collect(StringBuilder::new, StringBuilder::append, StringBuilder::append).toString();
}
static List<String> readCiphertext() {
List<String> cipherWords = new ArrayList<String>();
Scanner sc = new Scanner(System.in);
while (sc.hasNext()) {
cipherWords.add(sc.next());
}
sc.close();
return cipherWords;
}
static List<String> readDictionary() throws Throwable {
List<String> dictionary = new ArrayList<String>();
Scanner sc = new Scanner(new File(DICTIONARY_FILE_PATH));
while (sc.hasNext()) {
dictionary.add(sc.next().toLowerCase());
}
sc.close();
return dictionary;
}
}