银行家算法java实验

以下是一个使用Java实现银行家算法的示例：

import java.util.Arrays;

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; // 可利用资源向量
    private int[] safeSequence; // 安全序列

    public BankerAlgorithm(int[][] max, int[][] allocation, int[] available) {
        this.max = max;
        this.allocation = allocation;
        this.available = available;

        int m = max.length; // 进程数
        int n = max[0].length; // 资源种类数

        need = new int[m][n];
        safeSequence = new int[m];

        // 计算需求矩阵
        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                need[i][j] = max[i][j] - allocation[i][j];
            }
        }
    }

    public boolean isSafe() {
        int m = max.length; // 进程数
        int n = max[0].length; // 资源种类数

        boolean[] finish = new boolean[m]; // 完成标记数组
        int[] work = Arrays.copyOf(available, n); // 可利用资源向量的副本

        int count = 0; // 完成进程数

        while (count < m) {
            boolean found = false;

            for (int i = 0; i < m; i++) {
                if (!finish[i] && isNeedLessOrEqual(work, need[i])) {
                    // 分配资源
                    for (int j = 0; j < n; j++) {
                        work[j] += allocation[i][j];
                    }

                    safeSequence[count] = i;
                    finish[i] = true;
                    count++;
                    found = true;
                }
            }

            if (!found) {
                return false; // 无法找到安全序列
            }
        }

        return true; // 找到安全序列
    }

    private boolean isNeedLessOrEqual(int[] work, int[] need) {
        for (int i = 0; i < work.length; i++) {
            if (work[i] < need[i]) {
                return false;
            }
        }
        return true;
    }

    public int[] getSafeSequence() {
        return safeSequence;
    }
}

使用示例：

public class Main {
    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()) {
            int[] safeSequence = bankerAlgorithm.getSafeSequence();
            System.out.println("安全序列: " + Arrays.toString(safeSequence));
        } else {
            System.out.println("无法找到安全序列");
        }
    }
}