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November 28, 2016 18:46
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Design an efficient algorithm to solve the following scheduling problem. Provide a pseudocode and a worst case complexity analysis for your algorithm. You are given a set of n jobs with a processing time ti and a weight wi for each job. You want to order the jobs so as to minimize the weighted some of the completion times, n i ii Cw 1 . Exam…
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import java.util.SortedMap; | |
import java.util.TreeMap; | |
import java.util.Vector; | |
public class SchedulingProblem { | |
static Vector<Integer> processTime = new Vector<>(); | |
static Vector<Integer> processWeight = new Vector<>(); | |
static SortedMap<Integer, Double> timeWeightRatio = new TreeMap<Integer, Double>() { | |
}; | |
static int number = 2; | |
public static void main(String[] args) { | |
processTime.add(1); | |
processWeight.add(10); | |
processTime.add(3); | |
processWeight.add(2); | |
for (int i = 0; i < number; i++) { // O(N) | |
timeWeightRatio.put(i, processWeight.get(i) / (processTime.get(i) * 1.0)); // O(log(n)) | |
} | |
// ------------ O(nlog(n)) | |
int sum = 0, tmpTime = 0; | |
while (timeWeightRatio.size() > 0) { // O(n) | |
tmpTime += processTime.get(timeWeightRatio.firstKey()); // O(n) | |
sum += processWeight.get(timeWeightRatio.firstKey()) * tmpTime; // O(n) | |
System.out.print(processWeight.get(timeWeightRatio.firstKey()) + " * " + tmpTime + ((timeWeightRatio.size() > 1) ? " + " : " = " + sum)); | |
timeWeightRatio.remove(timeWeightRatio.firstKey()); // O(log(n)) | |
} | |
// >>>> O(nlog(n)) | |
} | |
} |
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10 * 1 + 2 * 4 = 18 |
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