最大子串匹配

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#string #import #list #null #date #class

最大子串匹配

/**
 * 
 */
package com.daniel.test;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;
import java.util.Map.Entry;

/**
 * @author Dianel Cao
 * @date   2007-4-10
 * @time   下午05:29:42
 *
 */
public class StringPattern {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		getMaxPattern("CABA","AABCABAC");
	}
	
	public static void getMaxPattern(String strA, String strB) {
		//只要有一个null，就返回null
		if (strA == null || strB == null || strA.trim().equals("") ||strB.trim().equals("")){
			System.out.println("");
			return;
		}
		int lengthA = strA.length();
		int lengthB = strB.length();
		String longStr = lengthA > lengthB ? strA : strB;
		String shortStr = lengthA > lengthB ? strB : strA;
		Map<Integer,List<String>> maxSubstrList = new TreeMap<Integer,List<String>>();
		for (int length = shortStr.length(); length > 0; length--) {
			for (int startIndex = 0; startIndex <= shortStr.length() - length; startIndex++) {
				String substr = shortStr.substring(startIndex, startIndex + length);
				if (longStr.indexOf(substr) > -1) {
					int len = substr.length();
					List<String> list;
					if (maxSubstrList.containsKey(len)){
						list = (List<String>)maxSubstrList.get(len);
					}else{
						list = new ArrayList<String>();
					}
					if (!list.contains(substr)){
						list.add(substr);
					}
					maxSubstrList.put(len, list);
				}
			}
		}
		// 找到最大匹配子串
		if (maxSubstrList.size() == 0){
			return;
		}else{
			Iterator<Entry<Integer,List<String>>> it = maxSubstrList.entrySet().iterator();
			Entry<Integer,List<String>> entry = it.next();
			while (it.hasNext()){
				entry = it.next();
			}
			List<String> maxList = entry.getValue();
			for(String str:maxList){
				System.out.println(str);
			}
		}
	}

}