银行家算法代码c++

银行家算法是一种用于避免死锁的资源分配算法。下面是一个简单的银行家算法的C++代码示例：

#include <iostream>
#include <vector>

using namespace std;

// 定义进程的最大需求矩阵
vector<vector<int>> maxDemand = {{7, 5, 3},
                                 {3, 2, 2},
                                 {9, 0, 2},
                                 {2, 2, 2},
                                 {4, 3, 3}};

// 定义系统当前可用资源向量
vector<int> available = {3, 3, 2};

// 定义进程已分配资源矩阵
vector<vector<int>> allocation = {{0, 1, 0},
                                  {2, 0, 0},
                                  {3, 0, 2},
                                  {2, 1, 1},
                                  {0, 0, 2}};

// 定义进程还需要资源矩阵
vector<vector<int>> need(5, vector<int>(3));

// 定义进程数量和资源数量
int numProcesses = 5;
int numResources = 3;

// 初始化进程还需要资源矩阵
void initNeedMatrix() {
    for (int i = 0; i < numProcesses; i++) {
        for (int j = 0; j < numResources; j++) {
            need[i][j] = maxDemand[i][j] - allocation[i][j];
        }
    }
}

// 检查进程是否满足资源需求
bool checkProcess(int process, vector<int>& work, vector<bool>& finish) {
    for (int i = 0; i < numResources; i++) {
        if (need[process][i] > work[i]) {
            return false;
        }
    }
    return true;
}

// 执行银行家算法
bool bankerAlgorithm() {
    vector<int> work = available;
    vector<bool> finish(numProcesses, false);
    vector<int> safeSequence;

    int count = 0;
    while (count < numProcesses) {
        bool found = false;
        for (int i = 0; i < numProcesses; i++) {
            if (!finish[i] && checkProcess(i, work, finish)) {
                for (int j = 0; j < numResources; j++) {
                    work[j] += allocation[i][j];
                }
                finish[i] = true;
                safeSequence.push_back(i);
                found = true;
                count++;
            }
        }
        if (!found) {
            return false;
        }
    }

    cout << "Safe sequence: ";    for (int i = 0; i < numProcesses; i++) {
        cout << safeSequence[i] << " ";
    }
    cout << endl;

    return true;
}

int main() {
    initNeedMatrix();
    if (bankerAlgorithm()) {
        cout << "System is safe." << endl;
    } else {
        cout << "System is unsafe." << endl;
    }

    return 0;
}