银行家算法实验java

以下是一个简单的Java实现银行家算法的示例代码：

import java.util.Scanner;

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

    public BankerAlgorithm(int[][] max, int[][] allocation, int[] available) {
        this.max = max;
        this.allocation = allocation;
        this.available = available;
        this.processNum = max.length;
        this.resourceNum = available.length;
        this.need = new int[processNum][resourceNum];
        for (int i = 0; i < processNum; i++) {
            for (int j = 0; j < resourceNum; j++) {
                need[i][j] = max[i][j] - allocation[i][j];
            }
        }
    }

    public boolean isSafe() {
        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]) {
                    boolean temp = true;
                    for (int j = 0; j < resourceNum; j++) {
                        if (need[i][j] > work[j]) {
                            temp = false;
                            break;
                        }
                    }
                    if (temp) {
                        for (int j = 0; j < resourceNum; j++) {
                            work[j] += allocation[i][j];
                        }
                        finish[i] = true;
                        flag = true;
                        count++;
                    }
                }
            }
            if (!flag) {
                return false;
            }
        }
        return true;
    }

    public boolean requestResource(int pid, int[] request) {
        for (int i = 0; i < resourceNum; i++) {
            if (request[i] > need[pid][i] || request[i] > available[i]) {
                return false;
            }
        }
        for (int i = 0; i < resourceNum; i++) {
            available[i] -= request[i];
            allocation[pid][i] += request[i];
            need[pid][i] -= request[i];
        }
        return true;
    }

    public void releaseResource(int pid, int[] release) {
        for (int i = 0; i < resourceNum; i++) {
            available[i] += release[i];
            allocation[pid][i] -= release[i];
            need[pid][i] += release[i];
        }
    }

    public static void main(String[] args) {
        int[][] max = {{7, 5, 3}, {3, 2, 2}, {9, 0, 2}, {2, 2, 2}, {4, 3, 3}};
        int[][] allocation = {{0, 1, 0}, {2, 0, 0}, {3, 0, 2}, {2, 1, 1}, {0, 0, 2}};
        int[] available = {3, 3, 2};
        BankerAlgorithm bankerAlgorithm = new BankerAlgorithm(max, allocation, available);
        if (bankerAlgorithm.isSafe()) {
            System.out.println("当前状态安全！");
        } else {
            System.out.println("当前状态不安全！");
        }
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入请求资源的进程编号：");
        int pid = scanner.nextInt();
        System.out.print("请输入请求的资源向量：");
        int[] request = new int[bankerAlgorithm.resourceNum];
        for (int i = 0; i < bankerAlgorithm.resourceNum; i++) {
            request[i] = scanner.nextInt();
        }
        if (bankerAlgorithm.requestResource(pid, request)) {
            if (bankerAlgorithm.isSafe()) {
                System.out.println("当前状态安全！");
            } else {
                System.out.println("当前状态不安全！");
                bankerAlgorithm.releaseResource(pid, request);
            }
        } else {
            System.out.println("请求被拒绝！");
        }
    }
}