lpt.cpp

来自「常用算法与数据结构原代码」· C++ 代码 · 共 52 行

// machine scheduling using LPT rule

#include <iostream.h>
#include "hsort.h"
#include "minheap.h"
#include "lptnodes.h"

template <class T>
void LPT(T a[], int n, int m)
{// Construct an m machine LPT schedule.
	if (n <= m) 
	{
		cout << "Schedule one job per machine." << endl;
		return;
	}
	
	HeapSort(a,n); // in ascending order
	// initialize m machines and the min heap
	MinHeap<MachineNode> H(m);
	MachineNode x;
	for (int i = 1; i <= m; i++) 
	{
		x.avail = 0;
		x.ID = i;
		H.Insert(x);
	}
	
	// construct schedule
	for (i = n; i >= 1; i--) 
	{
		H.DeleteMin(x);  // get first free machine
		cout << "Schedule job " << a[i].ID 
			 << " on machine " << x.ID << " from "
			 << x.avail << " to "
		     << (x.avail + a[i].time) << endl;
		x.avail += a[i].time;  // new avail time
		H.Insert(x);
	}
}

void main(void)
{
	JobNode a[11];
	int n = 10;
	for (int i = 1; i <= n; i++) 
	{
		a[i].time = 2 * i * i;
		a[i].ID = i;
	}
	LPT(a,n,3);
}