用java写一个银行家算法

银行家算法是一种死锁避免算法，用于管理资源的分配。以下是一个Java语言实现的银行家算法：

import java.util.Scanner;

public class BankerAlgorithm {
    private int[][] max; // 最大需求矩阵
    private int[][] allocation; // 分配矩阵
    private int[][] need; // 需求矩阵
    private int[] available; // 可用资源向量
    private int[] work; // 工作向量
    private int[] safeSequence; // 安全序列
    private boolean[] finish; // 是否完成标志
    private int n; // 进程数
    private int m; // 资源种类数
    private Scanner scanner;

    public BankerAlgorithm() {
        scanner = new Scanner(System.in);
        System.out.print("请输入进程数n：");
        n = scanner.nextInt();
        System.out.print("请输入资源种类数m：");
        m = scanner.nextInt();
        max = new int[n][m];
        allocation = new int[n][m];
        need = new int[n][m];
        available = new int[m];
        work = new int[m];
        safeSequence = new int[n];
        finish = new boolean[n];

        // 初始化各矩阵和向量
        System.out.println("请输入最大需求矩阵Max：");
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                max[i][j] = scanner.nextInt();
            }
        }

        System.out.println("请输入分配矩阵Allocation：");
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; 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Available：");
        for (int i = 0; i < m; i++) {
            available[i] = scanner.nextInt();
        }
    }

    // 检查进程是否能够获得资源
    public boolean check(int i) {
        for (int j = 0; j < m; j++) {
            if (need[i][j] > work[j]) {
                return false;
            }
        }
        return true;
    }

    // 安全性检查
    public boolean safetyCheck() {
        int count = 0;
        for (int i = 0; i < m; i++) {
            work[i] = available[i];
        }
        for (int i = 0; i < n; i++) {
            finish[i] = false;
        }
        while (count < n) {
            boolean flag = false;
            for (int i = 0; i < n; i++) {
                if (!finish[i] && check(i)) {
                    for (int j = 0; j < m; j++) {
                        work[j] += allocation[i][j];
                    }
                    safeSequence[count++] = i;
                    finish[i] = true;
                    flag = true;
                }
            }
            if (!flag) {
                return false;
            }
        }
        return true;
    }

    // 资源分配
    public void resourceAllocation() {
        System.out.println("请输入请求资源的进程编号和请求向量：");
        int pid = scanner.nextInt();
        int[] request = new int[m];
        for (int i = 0; i < m; i++) {
            request[i] = scanner.nextInt();
        }
        for (int i = 0; i < m; i++) {
            if (request[i] > need[pid][i] || request[i] > available[i]) {
                System.out.println("请求无法满足！");
                return;
            }
        }
        for (int i = 0; i < m; i++) {
            available[i] -= request[i];
            allocation[pid][i] += request[i];
            need[pid][i] -= request[i];
        }
        if (safetyCheck()) {
            System.out.println("分配成功！");
        } else {
            System.out.println("分配失败！");
            for (int i = 0; i < m; i++) {
                available[i] += request[i];
                allocation[pid][i] -= request[i];
                need[pid][i] += request[i];
            }
        }
    }

    // 打印输出矩阵和向量
    public void print() {
        System.out.println("Max矩阵：");
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                System.out.print(max[i][j] + "\t");
            }
            System.out.println();
        }

        System.out.println("Allocation矩阵：");
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                System.out.print(allocation[i][j] + "\t");
            }
            System.out.println();
        }

        System.out.println("Need矩阵：");
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                System.out.print(need[i][j] + "\t");
            }
            System.out.println();
        }

        System.out.println("Available向量：");
        for (int i = 0; i < m; i++) {
            System.out.print(available[i] + "\t");
        }
        System.out.println();

        System.out.println("安全序列：");
        for (int i = 0; i < n; i++) {
            System.out.print(safeSequence[i] + " ");
        }
        System.out.println();
    }

    public static void main(String[] args) {
        BankerAlgorithm banker = new BankerAlgorithm();
        banker.print();
        banker.resourceAllocation();
        banker.print();
    }
}

这个程序实现了银行家算法的基本功能，包括输入数据、安全性检查、资源分配等。用户可以根据自己的需要进行修改和扩展。