Question:

generate two different random integers, s and t, which are different for each message. s is called the start code and t is called the end code.
The value of t is transmitted as the first integer in the encoded output. Then for every integer i in the message, the integer s is sent followed by a
randomly generated sequence L of 1 or more integers that sum to i with the constraint that neither s nor t appears in the sequence.

The entire message is terminated by a single t value. For example, if the message is 3, 21, 5 and the start and end codes are 11 and -91, the message might be transmitted as -91, 11, -1, 5, 2, -3, 11, 21, 11, 4, 0, 1 , -91 (where 3 is represented as -1 + 5 + 2 - 3, 21 is represented as itself and 5 is represented as 4 + 0 + 1).

Non-functional requirements: your program may not use arrays!

Input  
-91 11 -1 5 2 -3 11 21 11 4 0 1 -91

Output
3
21
5
Input
0 1 2 3 4 1 -1 -2 -3 0  

output
9
-6

拜托各位帮帮忙吧，我人在澳洲，刚到这边，没几个会编程的朋友，大部分都是学商科的，这个是学校的作业，我实在是不太明白怎么做。只能求教于网络了。拜托大家