Implementation of banker algorithm

理解死锁、死锁避免、死锁预防等基本概念，死锁的产生原因（随机算法），理解死锁的解决办法（银行家算法）。(Understanding deadlock, deadlock avoidance, deadlock prevention and other basic concepts, the causes of deadlock (random algorithm), understand the solution of deadlock (banker's algorithm).)