Java Program to Implement First Fit Decreasing for 1-D Objects and M Bins

Code:

import java.util.Scanner;

public class First_Fit_Decreasing_Bin_Packing
{
public static void main(String args[])
{
System.out
.println("BIN - PACKING Algorithm 1D Objects(First Fit Decreasing)");
System.out.println("Enter the number of items in Set: ");
Scanner sc = new Scanner(System.in);
int n = sc.nextInt();
System.out.println("Enter " + n + " items:");
int[] a = new int[n];
for (int i = 0; i < n; i++)
a[i] = sc.nextInt();
System.out.println("Enter the bin size: ");
int size = sc.nextInt();
int[] sequence = sort(a);
binPacking(sequence, size, n);
sc.close();
}

public static void binPacking(int[] a, int size, int n)
{
int binCount = 0;
int[] binValues = new int[n];
for (int i = 0; i < binValues.length; i++)
binValues[i] = size;

for (int i = 0; i < n; i++)
for (int j = 0; j < binValues.length; j++)
{
if (binValues[j] - a[i] >= 0)
{
binValues[j] -= a[i];
break;
}
}

for (int i = 0; i < binValues.length; i++)
if (binValues[i] != size)
binCount++;

System.out
.println("Number of bins required using first fit decreasing algorithm is:"
+ binCount);
}

static int[] sort(int[] sequence)
{
// Bubble Sort descending order
for (int i = 0; i < sequence.length; i++)
for (int j = 0; j < sequence.length - 1; j++)
if (sequence[j] < sequence[j + 1])
{
sequence[j] = sequence[j] + sequence[j + 1];
sequence[j + 1] = sequence[j] - sequence[j + 1];
sequence[j] = sequence[j] - sequence[j + 1];
}
return sequence;
}
}


Output:

BIN - PACKING Algorithm for 1D Objects(First Fit Decreasing)
Enter the number of items in Set: 
9
Enter 9 items:
4 
1
2
5
3
2
3
6
3
Enter the bin size: 
6
Number of bins required using first fit decreasing algorithm is:5



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