银行家算法Java实现

银行家算法是一种避免死锁的算法，它通过动态地分配资源来避免进程因争夺资源而产生死锁。下面是银行家算法的Java实现：

import java.util.Scanner;

public class BankerAlgorithm {
    private int[][] need; // 需求矩阵
    private int[][] allocation; // 分配矩阵
    private int[][] max; // 最大需求矩阵
    private int[] available; // 可用资源向量
    private int processNum; // 进程数
    private int resourceNum; // 资源数

    public BankerAlgorithm(int[][] need, int[][] allocation, int[][] max, int[] available) {
        this.need = need;
        this.allocation = allocation;
        this.max = max;
        this.available = available;
        this.processNum = allocation.length;
        this.resourceNum = available.length;    }

    // 判断是否满足需求
    private boolean check(int[] work, boolean[] finish, int[] need, int[] allocation) {
        for (int i = 0; i < resourceNum; i++) {
            if (need[i] > work[i]) {
                return false;
            }
        }
        for (int i = 0; i < resourceNum; i++) {
            work[i] += allocation[i];
        }
        finish[processNum] = true;
        return true;
    }

    // 执行银行家算法
    public boolean execute() {
        boolean[] finish = new boolean[processNum];
        int[] work = new int[resourceNum];
        for (int i = 0; i < resourceNum; i++) {
            work[i] = available[i];
        }
        int count = 0;
        while (count < processNum) {
            boolean flag = false;
            for (int i = 0; i < processNum; i++) {
                if (!finish[i] && check(work, finish, need[i], allocation[i])) {
                    flag = true;
                    count++;
                }
            }
            if (!flag) {
                return false;
            }
        }
        return true;
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入进程数：");
        int processNum = scanner.nextInt();
        System.out.print("请输入资源数：");
        int resourceNum = scanner.nextInt();
        int[][] max = new int[processNum][resourceNum];
        int[][] allocation = new int[processNum][resourceNum];
        int[][] need = new int[processNum][resourceNum];
        int[] available = new int[resourceNum];
        System.out.println("请输入最大需求矩阵：");
        for (int i = 0; i < processNum; i++) {
            for (int j = 0; j < resourceNum; j++) {
                max[i][j] = scanner.nextInt();
            }
        }
        System.out.println("请输入分配矩阵：");
        for (int i = 0; i < processNum; i++) {
            for (int j = 0; j < resourceNum; j++) {
                allocation[i][j] = scanner.nextInt();
                need[i][j] = max[i][j] - allocation[i][j];
            }
        }
        System.out.println("请输入可用资源向量：");
        for (int i = 0; i < resourceNum; i++) {
            available[i] = scanner.nextInt();
        }
        BankerAlgorithm bankerAlgorithm = new BankerAlgorithm(need, allocation, max, available);
        if (bankerAlgorithm.execute()) {
            System.out.println("系统是安全的！");
        } else {
            System.out.println("系统是不安全的！");
        }
    }
}