上一篇文章中介绍了正向最大匹配，可以看到有时候效果不是很好，这里在介绍一种逆向最大匹配的算法。词典和匹配的字符串都和上一篇文章相同

只是本算法是从后到前搜索字符串，然后找到最长的匹配结果输出。上代码

package com;


import java.util.ArrayList;
import java.util.List;


public class Segmentation1 {
	private List<String> dictionary = new ArrayList<String>();
	private String request = "北京大学生前来应聘";
	
	public void setDictionary() {
		dictionary.add("北京");
		dictionary.add("北京大学");
		dictionary.add("大学");
		dictionary.add("大学生");
		dictionary.add("生前");
		dictionary.add("前来");
		dictionary.add("应聘");
	}
	
	private boolean isIn(String s, List<String> list) {
		for(int i=0; i<list.size(); i++) {
			if(s.equals(list.get(i))) return true;
		}
		return false;
	}
	
	public String rightMax() {
		String response = "";
		String s = "";
		for(int i=request.length()-1; i>=0; i--) {
			s = request.charAt(i) + s;
			if(isIn(s, dictionary) && tailCount(s, dictionary)==1) {
				response = (s + "/") + response;
				s = "";
			} else if(tailCount(s, dictionary) > 0) {
				
			} else {
				response = (s + "/") + response;
				s = "";
			}
		}
		return response;
	}
	
	private int tailCount(String s, List<String> list) {
		int count = 0;
		for(int i=0; i<list.size(); i++) {
			if((s.length()<=list.get(i).length()) && (s.equals(list.get(i).substring(list.get(i).length()-s.length(), list.get(i).length())))) count ++;
		}
		return count;
	}
	
	public static void main(String[] args) {
		Segmentation1 seg = new Segmentation1();
		seg.setDictionary();
		String response2 = seg.rightMax();
		System.out.println(response2);
	}
}



可以看到运行结果是：北京/大学生/前来/应聘/
分词效果很好