worst_fit.java

// Java implementation of worst - Fit algorithm

public class worst_fit
{
	// Method to allocate memory to blocks as per worst fit
	// algorithm
	static void worstFit(int blockSize[], int m, int processSize[], int n)
	{
		// Stores block id of the block allocated to a
		// process
		int allocation[] = new int[n];
	
		// Initially no block is assigned to any process
		for (int i = 0; i < allocation.length; i++)
			allocation[i] = -1;
	
		// pick each process and find suitable blocks
		// according to its size ad assign to it
		for (int i=0; i<n; i++)
		{
			// Find the best fit block for current process
			int wstIdx = -1;
			for (int j=0; j<m; j++)
			{
				if (blockSize[j] >= processSize[i])
				{
					if (wstIdx == -1)
						wstIdx = j;
					else if (blockSize[wstIdx] < blockSize[j])
						wstIdx = j;
				}
			}
	
			// If we could find a block for current process
			if (wstIdx != -1)
			{
				// allocate block j to p[i] process
				allocation[i] = wstIdx;
	
				// Reduce available memory in this block.
				blockSize[wstIdx] -= processSize[i];
			}
		}
	
		System.out.println("\nProcess No."+"\tProcess Size"+"\tBlock no.");
		for (int i = 0; i < n; i++)
		{
			System.out.print(" " + (i+1) + "\t\t" + processSize[i] + "\t\t");
			if (allocation[i] != -1)
				System.out.print(allocation[i] + 1);
			else
				System.out.print("Not Allocated");
			System.out.println();
		}
	}
	
	// Driver Method
	public static void main(String[] args)
	{
		int blockSize[] = {100, 500, 200, 300, 600};
		int processSize[] = {212, 417, 112, 426};
		int m = blockSize.length;
		int n = processSize.length;
		
		worstFit(blockSize, m, processSize, n);
	}
}