SSTF.py

# -*- coding: utf-8 -*-
class SSTF:

    def __init__(self):
        pass

    # Calcula a diferença entre a cabeça e o possível proximo setor da fila.
    def calculateDifference(self, queue, head, diff):
        for i in range(len(diff)):
            diff[i][0] = abs(queue[i] - head)

    # Encontrar o próximo com a menor diferença
    def findMin(self, diff):
        min_diff = float('inf')
        index = -1
        for i in range(len(diff)):
            if not diff[i][1] and diff[i][0] < min_diff:
                min_diff = diff[i][0]
                index = i
        return index
        
    def shortestSeekTimeFirst(self, requisicoes, head):          
            if (len(requisicoes) == 0): 
                return
            
            length_req = len(requisicoes)

            diff = [[0, 0] for _ in range(length_req)] 
            
            seek_sequence = [0] * (length_req + 1) 
            
            for i in range(length_req): 
                seek_sequence[i] = head 
                self.calculateDifference(requisicoes, head, diff) 
                index = self.findMin(diff) 
                
                diff[index][1] = True

                head = requisicoes[index] 
        
            seek_sequence[len(seek_sequence) - 1] = head 

            return seek_sequence

def run(head, req):
    sstf = SSTF()
    lista = sstf.shortestSeekTimeFirst(req, head)
    out = ''
    for i in lista:
        out += str(i) + ','
        
    return out[3:-1]