【算法】程序猿不写代码是不对的13

package com.kingdz.algorithm.time201702;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

/**
* 算数表达式分解<br/>
* 程序的目的是将：(2+34)*5分解为List，其中分解后的结果为{(,2,+,34,),*,5}<br/>
*
* @author kingdz
*
*/
public class Algo07 {

/**
* 分隔符集合
*/
public static final String[] separator = { "(", ")", "[", "]", "{", "}", "+", "-", "*", "/" };

public static void main(String[] args) {
String question = "(21+34)*5+12*34";
List<String> result = dismantle(question);
System.out.println(Arrays.toString(result.toArray()));
}

/**
* 分解算法
*
* @param question
* @return
*/
static List<String> dismantle(String question) {
// 将字符串数组转换为set方便判断
List<String> separatorList = new ArrayList<String>();
int maxLen = 0;
for (String str : separator) {
int len = str.length();
if (len > maxLen) {
maxLen = len;
}
separatorList.add(str);
}

Collections.sort(separatorList, new Comparator<String>() {

public int compare(String o1, String o2) {
if (o1 == null || o2 == null) {
return 0;
}
return o2.length() - o1.length();
}
});

List<String> ret = new ArrayList<String>();
// 确定开始和结尾来分解字符串
int start = 0;
int end = Math.min(start + maxLen, question.length());
while (start < question.length() && start < end) {
String sub = question.substring(start, end);

// 是否包含分解字符串
if (separatorList.contains(sub)) {
ret.add(sub);
start = end;
end = Math.min(start + maxLen, question.length());
} else {
if (end - start == 1) {
if (ret.size() == 0) {
// 如果集合为空则直接插入
ret.add(sub);
start = end;
end = Math.min(start + maxLen, question.length());
} else {
// 如果不为空，则需要判断最后一位是否为分隔符
String lastIn = ret.get(ret.size() - 1);
if (separatorList.contains(lastIn)) {
ret.add(sub);
} else {
ret.set(ret.size() - 1, lastIn + sub);
}
start = end;
end = Math.min(start + maxLen, question.length());
}
} else {
// 将end逐渐较小，保证轮询所有长度的分割字符串数组
end--;
}
}
}
return ret;
}
}