浅析12306售票算法(java版)

import java.math.BigDecimal;
public class MainTest {
public static void main(String[] args) {
String ticketFlag = "";
int beginStation = ;
int endStation = ;
long beginTime = System.currentTimeMillis();
String result = orderTicket(ticketFlag, beginStation, endStation);
if (result.equals(ticketFlag)) {
System.out.println("订票失败");
} else {
System.out.println("订票后的结果：" + result);
// 如果要取消的话，就进行这个操作
String b = buildTicket(ticketFlag.length(), beginStation,
endStation);
System.out.println("释放后的结果：" + releaseTicket(ticketFlag, b));
}
long endTime = System.currentTimeMillis();
System.out.println("耗时：" + (endTime - beginTime));
}
/**
* 订票
* 
* @param ticketFlag
* @param beginStation
* @param endStation
* @return
*/
private static String orderTicket(String ticketFlag, int beginStation,
int endStation) {
String result = "";
if (checkCanTicket(ticketFlag, beginStation, endStation)) {
String b = buildTicket(ticketFlag.length(), beginStation,
endStation);
String currentTicked = toTicket(ticketFlag, b);
System.out.println("预占票前结果：" + ticketFlag);
result = currentTicked;
} else {
result = ticketFlag;
}
;
return result;
}
/**
* 取消已定票
* 
* @param ticketFlag
* @param b
* @return
*/
private static String releaseTicket(String ticketFlag, String b) {
StringBuilder tempSt = new StringBuilder("");
int length = ticketFlag.length();
for (int i = ; i < length; i++) {
char tempA = ticketFlag.charAt(i);
char tempB = b.charAt(i);
if (tempA == '' && tempB == '') {
tempSt.append("");
} else {
tempSt.append(tempA);
}
}
return tempSt.toString();
}
/**
* 创建区间占位票
* 
* @param length
* @param beginStation
* @param endStation
* @return
*/
private static String buildTicket(int length, int beginStation,
int endStation) {
StringBuilder st = new StringBuilder("");
for (int i = ; i < length; i++) {
if (i >= beginStation && i < endStation) {
st.append("");
} else {
st.append("");
}
}
System.out.println("创建区间票：" + st.toString());
return st.toString();
}
/**
* 生成订票后的结果
* 
* @param ticketFlag
* @param b
* @return
*/
private static String toTicket(String ticketFlag, String b) {
StringBuilder tempSt = new StringBuilder("");
int length = ticketFlag.length();
for (int i = ; i < length; i++) {
char tempA = ticketFlag.charAt(i);
char tempB = b.charAt(i);
if (tempA == '' || tempB == '') {
tempSt.append("");
} else {
tempSt.append(tempA);
}
}
return tempSt.toString();
}
/**
* 是否可以订票
* 
* @param ticketFlag
* @param beginStation
* @param endStation
* @return
*/
private static boolean checkCanTicket(String ticketFlag, int beginStation,
int endStation) {
boolean result = false;
String tempTicket = ticketFlag.substring(beginStation, endStation);
BigDecimal b = new BigDecimal(tempTicket);
if (b.equals(new BigDecimal(""))) {
result = true;
}
return result;
}
}