《Cracking the Coding Interview》——第16章：线程与锁——题目4

2014-04-27 20:06

题目：设计一个类，只有在不产生死锁的时候才分配资源。

解法：不太清楚这个题是要分配何种资源，以何种形式？所以没能动手写个可运行的代码，只是闲扯了几句理论分析。

代码：

// 16.4 Design a class which provides a lock only if no deadlock would take place.
1. The class will maintain a list of all locks that would be requested by different processes.
    private Vector<Lock> locks;
2. The class will have a real-time record of which processes are using which locks. Mapping the process ID with a queue recording the locks it is using.
    private HashMap<int, Queue<Lock> > lockOccupations;
3. The class will perform deadlock detection before assigning a certain lock to a certain process.
    private bool deadLockDetection(int processID, int lockID);
4. The class will provide a public method to assign a lock to a process.
    public bool getLock(int processID, int lockID);

About dead lock detection:
    Generally, dead lock detection is about detecting a loop in a directed graph. Using DFS will be a solution.