java银行家算法代码

当然，下面是一个简单的Java实现的银行家算法代码示例：

import java.util.Arrays;

public class BankerAlgorithm {
    private int processCount;  // 进程数
    private int resourceCount;  // 资源种类数
    private int[] available;  // 可用资源数组
    private int[][] max;  // 最大需求矩阵
    private int[][] allocation;  // 分配矩阵
    private int[][] need;  // 需求矩阵

    public BankerAlgorithm(int processCount, int resourceCount) {
        this.processCount = processCount;
        this.resourceCount = resourceCount;
        this.available = new int[resourceCount];
        this.max = new int[processCount][resourceCount];
        this.allocation = new int[processCount][resourceCount];
        this.need = new int[processCount][resourceCount];
    }

    public void setAvailable(int[] available) {
        this.available = available;
    }

    public void setMax(int processIndex, int[] max) {
        this.max[processIndex] = max;
    }

    public void setAllocation(int processIndex, int[] allocation) {
        this.allocation[processIndex] = allocation;
    }

    public boolean isSafeState() {
        boolean[] finish = new boolean[processCount];
        int[] work = Arrays.copyOf(available, resourceCount);
        int[][] tempNeed = new int[processCount][resourceCount];
        int[] safeSequence = new int[processCount];
        int count = 0;

        for (int i = 0; i < processCount; i++) {
            tempNeed[i] = Arrays.copyOf(need[i], resourceCount);
        }

        while (count < processCount) {
            boolean found = false;
            for (int i = 0; i < processCount; i++) {
                if (!finish[i] && isLessOrEqual(tempNeed[i], work)) {
                    for (int j = 0; j < resourceCount; j++) {
                        work[j] += allocation[i][j];
                    }
                    safeSequence[count++] = i;
                    finish[i] = true;
                    found = true;
                }
            }
            if (!found) {
                break;
            }
        }

        return count == processCount;
    }

    private boolean isLessOrEqual(int[] a, int[] b) {
        for (int i = 0; i < a.length; i++) {
            if (a[i] > b[i]) {
                return false;
            }
        }
        return true;
    }

    public static void main(String[] args) {
        BankerAlgorithm banker = new BankerAlgorithm(5, 3);

        int[] available = {3, 3, 2};
        banker.setAvailable(available);

        int[][] max = {
                {7, 5, 3},
                {3, 2, 2},
                {9, 0, 2},
                {2, 2, 2},
                {4, 3, 3}
        };
        for (int i = 0; i < banker.processCount; i++) {
            banker.setMax(i, max[i]);
        }

        int[][] allocation = {
                {0, 1, 0},
                {2, 0, 0},
                {3, 0, 2},
                {2, 1, 1},
                {0, 0, 2}
        };
        for (int i = 0; i < banker.processCount; i++) {
            banker.setAllocation(i, allocation[i]);
        }

        int[][] need = new int[banker.processCount][banker.resourceCount];
        for (int i = 0; i < banker.processCount; i++) {
            for (int j = 0; j < banker.resourceCount; j++) {
                need[i][j] = max[i][j] - allocation[i][j];
            }
        }

        boolean isSafe = banker.isSafeState();
        System.out.println("Is the state safe? " + isSafe);
    }
}

这个示例实现了银行家算法的安全性检查，通过判断系统是否处于安全状态来决定是否分配资源。在示例中，设置了5个进程和3个资源种类，分别为可用资源数组、最大需求矩阵、分配矩阵和需求矩阵。在 `main()` 方法中，设置了示例数据，并通过 `isSafeState()` 方法判断系统是否处于安全状态。