优先级调度算法C++

优先级调度算法是一种用于操作系统进程调度的算法。它根据进程的优先级来确定执行顺序，优先级较高的进程会被优先执行。下面是一个简单的优先级调度算法的伪代码示例:

1. 初始化就绪队列和优先级队列
2. 循环直到就绪队列为空:
3.     从就绪队列中选择优先级最高的进程
4.     执行该进程
5.     更新进程的优先级（如果需要）
6.     将执行完的进程从就绪队列中移除
7. 结束循环

在这个算法中，首先需要初始化就绪队列和优先级队列。就绪队列用于存储可以立即执行的进程，而优先级队列用于按照优先级进行排序。然后，不断选择优先级最高的进程执行，执行完毕后更新进程的优先级，并将执行完的进程从就绪队列中移除。最后，当就绪队列为空时结束循环。

相关问题

编制时间片轮转调度算法和静态优先级调度算法C++

时间片轮转调度算法的C++代码如下：

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

class Process {
public:
    int pid;
    int arrival_time;
    int burst_time;
    int remaining_time;

    Process(int pid, int arrival_time, int burst_time) {
        this->pid = pid;
        this->arrival_time = arrival_time;
        this->burst_time = burst_time;
        this->remaining_time = burst_time;
    }

    int execute(int time_slice) {
        if (remaining_time > time_slice) {
            remaining_time -= time_slice;
            return time_slice;
        } else {
            int time_executed = remaining_time;
            remaining_time = 0;
            return time_executed;
        }
    }
};

double round_robin_scheduling(vector<Process>& processes, int time_slice) {
    int n = processes.size();
    vector<Process> remaining_processes = processes;
    int current_time = 0;
    int waiting_time = 0;
    int turnaround_time = 0;

    while (!remaining_processes.empty()) {
        Process current_process = remaining_processes[0];
        remaining_processes.erase(remaining_processes.begin());
        if (current_process.arrival_time > current_time) {
            current_time = current_process.arrival_time;
        }
        int time_executed = current_process.execute(time_slice);
        current_time += time_executed;
        if (current_process.remaining_time == 0) {
            waiting_time += current_time - current_process.arrival_time - current_process.burst_time;
            turnaround_time += current_time - current_process.arrival_time;
        } else {
            remaining_processes.push_back(current_process);
        }
    }

    double avg_waiting_time = (double) waiting_time / n;
    double avg_turnaround_time = (double) turnaround_time / n;
    return avg_waiting_time;
}

静态优先级调度算法的C++代码如下：

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

class Process {
public:
    int pid;
    int arrival_time;
    int burst_time;
    int priority;

    Process(int pid, int arrival_time, int burst_time, int priority) {
        this->pid = pid;
        this->arrival_time = arrival_time;
        this->burst_time = burst_time;
        this->priority = priority;
    }

    void execute() {
        burst_time--;
    }
};

double static_priority_scheduling(vector<Process>& processes) {
    int n = processes.size();
    vector<Process> remaining_processes = processes;
    int current_time = 0;
    int waiting_time = 0;
    int turnaround_time = 0;

    while (!remaining_processes.empty()) {
        sort(remaining_processes.begin(), remaining_processes.end(), [](Process p1, Process p2){
            if (p1.priority == p2.priority) {
                return p1.arrival_time < p2.arrival_time;
            } else {
                return p1.priority > p2.priority;
            }
        });
        Process current_process = remaining_processes[0];
        remaining_processes.erase(remaining_processes.begin());
        if (current_process.arrival_time > current_time) {
            current_time = current_process.arrival_time;
        }
        current_process.execute();
        current_time++;
        if (current_process.burst_time == 0) {
            waiting_time += current_time - current_process.arrival_time - current_process.priority;
            turnaround_time += current_time - current_process.arrival_time;
        } else {
            remaining_processes.push_back(current_process);
        }
    }

    double avg_waiting_time = (double) waiting_time / n;
    double avg_turnaround_time = (double) turnaround_time / n;
    return avg_waiting_time;
}

优先级调度算法psa c++

优先级调度算法（Priority Scheduling Algorithm，PSA）是一种常见的进程调度算法，它根据进程的优先级来决定下一个要执行的进程。在 PSA 中，每个进程都有一个优先级，优先级高的进程先被执行，如果有多个进程的优先级相同，则按照先来先服务（First Come First Serve，FCFS）的原则进行调度。

在实现 PSA 算法时，可以使用一个优先队列来存储所有等待执行的进程，每次从队列中取出优先级最高的进程进行执行。当一个进程被创建时，它会被插入到队列中的合适位置，当一个进程完成时，它会被从队列中移除。

以下是一个使用 C++ 实现 PSA 算法的示例代码：

#include <iostream>
#include <queue>
using namespace std;

struct Process {
    int pid; // 进程 ID
    int priority; // 进程优先级
    int burst_time; // 进程执行时间
};

// 定义一个比较函数，用于将进程按照优先级从高到低排序
struct Compare {
    bool operator()(Process const& p1, Process const& p2) {
        return p1.priority < p2.priority;
    }
};

int main() {
    // 创建一个优先队列，用于存储等待执行的进程
    priority_queue<Process, vector<Process>, Compare> pq;

    // 添加一些进程到队列中
    pq.push({1, 3, 10});
    pq.push({2, 1, 5});
    pq.push({3, 2, 8});

    // 依次执行队列中的进程
    while (!pq.empty()) {
        Process p = pq.top();
        pq.pop();
        cout << "Executing process " << p.pid << " with priority " << p.priority << endl;
    }

    return 0;
}

在上面的代码中，我们使用了一个结构体来表示进程，其中包含了进程的 ID、优先级和执行时间。我们还定义了一个比较函数 Compare，用于将进程按照优先级从高到低排序。最后，我们创建了一个优先队列 pq，并将一些进程添加到队列中。在执行过程中，我们每次从队列中取出优先级最高的进程进行执行。