找到一个单词的所有相似单词

相似单词为 只差一位字母的单词，练习Map容器

package chapter4;import java.util.*;import java.util.Map.Entry;/* * 说明：找到一个单词的所有相似单词 例如： wine 和 dine wind 和wing 只有一个字母不同 */public class TreeMapTest {/* * 判断2个单词是否指差一个字母 */public static boolean oneCharOff(String s1, String s2) {if (s1.length() != s2.length())return false;int diff = 0;for (int i = 0; i < s1.length() - 1; i++) {if (s1.charAt(i) != s2.charAt(i))diff++;if (diff > 1)return false;}return diff == 1;}/* * 打印方法 */public static void print(Map<String, List<String>> map) {for (Map.Entry<String, List<String>> entry : map.entrySet()) {List<String> words = entry.getValue();System.out.print(entry.getKey() + ":");for (int i = 0; i < words.size(); i++) {System.out.print(words.get(i) + " ");}System.out.println();}}/** * 方法名：computeWords 说明：方法1 */public static Map<String, List<String>> computeWords1(List<String> words) {Map<String, List<String>> map = new TreeMap<String, List<String>>();String[] word = new String[words.size()];words.toArray(word);for (int i = 0; i < word.length; i++) {for (int j = i + 1; j < word.length; j++) {if (oneCharOff(word[i], word[j])) {update(map, word[i], word[j]);// 互为相似单词update(map, word[j], word[i]);}}}return map;}/** * 方法名：update 说明：更新 */private static <KeyType> void update(Map<KeyType, List<String>> map,KeyType key, String s) {List<String> words = map.get(key);if (words == null) {words = new ArrayList<String>();map.put(key, words);}words.add(s);}/** * 方法名：groupByLength 说明：先将给的单词按照长度分组 */private static Map<Integer, List<String>> groupByLength(List<String> words) {Map<Integer, List<String>> map = new TreeMap<Integer, List<String>>();for (String s : words)update(map, s.length(), s);return map;}/** * 方法名：computeWord 说明：方法2 */public static Map<String, List<String>> computeWords2(List<String> words) {Map<String, List<String>> map = new TreeMap<String, List<String>>();for (Entry<Integer, List<String>> entry : groupByLength(words).entrySet()) {String[] word = new String[entry.getValue().size()];entry.getValue().toArray(word);for (int i = 0; i < word.length; i++) {for (int j = i + 1; j < word.length; j++) {if (oneCharOff(word[i], word[j])) {update(map, word[i], word[j]);// 互为相似单词update(map, word[j], word[i]);}}}}return map;}/** * 方法名：computeWords3  * 说明：该方法效率最高。首先也是按照长度分组，分组完了之后，对每组分别做以下操作： * 1：从头到尾分别去掉每个单词的一位字母。将剩下的作为一个键，该单词作为值 放到新建的 * map<String,List<String>>reToWord里 * 2：遍历reToWord，找到size>=2的，(因为只有>=2的 才代表含有相似的)例如wine和wane 当去掉第2位 * 时，首先wine会进List,wane匹配到了wne也会进去，所以是2个 */public static Map<String, List<String>> computeWords3(List<String> words) {Map<String, List<String>> adjWords = new TreeMap<String, List<String>>();Map<Integer, List<String>> wordsByLength = new TreeMap<Integer, List<String>>();for (String w : words)update(wordsByLength, w.length(), w);for (Map.Entry<Integer, List<String>> entry : wordsByLength.entrySet()) {List<String> groupsWords = entry.getValue();int groupNum = entry.getKey();for (int i = 0; i < groupNum; i++) {Map<String, List<String>> repToWord = new TreeMap<String, List<String>>();for (String str : groupsWords) {String rep = str.substring(0, i) + str.substring(i + 1);update(repToWord, rep, str);}for (List<String> wordClique : repToWord.values())if (wordClique.size() >= 2)for (String s1 : wordClique)for (String s2 : wordClique)if (s1 != s2)update(adjWords, s1, s2);}}return adjWords;}public static void main(String[] args) {// TODO Auto-generated method stubList<String> list = new ArrayList<String>();list.add("wane");list.add("wine");list.add("aine");list.add("dine");list.add("anew");list.add("kine");list.add("qine");list.add("eine");list.add("rine");print(computeWords1(list));System.out.println();print(computeWords2(list));System.out.println();print(computeWords3(list));}}