ElectoralCounts.java

import java.util.Arrays;
import java.util.Vector;


public class ElectoralCounts {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		int[] votes = { 9, 3, 11, 6, 55, 9, 7, 3, 3, 29, 16, 4, 4, 20, 11, 6, 6, 8, 8, 4, 10, 11, 16, 10, 6, 10, 3, 5, 6, 4, 14, 5, 29, 15, 3, 18, 7, 7, 20, 4, 9, 3, 11, 38, 6, 3, 13, 12, 5, 10, 3 };
		int sum = 0;
		for (int i=0; i < votes.length; i++) {
			sum+=votes[i];
		}
		calculateMaxSum(votes, sum/2);		
	}
	
	private static long path_count = 0;
	private static long bad_items = 0;
	private static Vector<Integer> soln = new Vector<Integer>();
	
	public static void PathCount(int [][]M, int [] votes, int i, int j)
	{
		if (i < 0 || j < 0)
		{
			bad_items++;
			return;
		}
		
		if (i == 0 || j == 0)
		{
			//printOutSolution();
			path_count++;
			if (path_count % 100000000 == 0)
				System.out.println("Count: " + path_count);
			return;
		}
		else 
		{
			int w = j;
			int w_i = votes[i-1];
			
			if (w < w_i) {
				M[i][w]= M[i-1][w];
				PathCount(M, votes, i-1, w);
			}
			else {
				int choiceAddElement = votes[i-1] + M[i-1][w-w_i];
				int choiceIgnoreElement = M[i-1][w];
				if (choiceAddElement == choiceIgnoreElement) 
				{
					PathCount (M, votes, i-1, w);
					//soln.add(w_i);
					PathCount (M, votes, i-1, w-w_i);
					//soln.removeElement(w_i);

				}
				else {
					if (choiceAddElement > choiceIgnoreElement) {
						M[i][w] = choiceAddElement;
						//soln.add(w_i);
						PathCount (M, votes, i-1, w-w_i);
						//soln.removeElement(w_i);
					}
					else {
						M[i][w] = choiceIgnoreElement;
						PathCount (M, votes, i-1, w);
					}
				}
			}		
		}
	}

	private static void printOutSolution() {
		int sum = 0;
		for (int k=0; k < soln.size(); k++)
		{
			sum += soln.elementAt(k);
		}
		Object[] solnArray = soln.toArray();
		//Arrays.sort(solnArray);
		System.out.println(sum + ": " + Arrays.toString(solnArray));
		//soln.clear();
	}
	
	public static void calculateMaxSum(int[] votes, int sum) {
		int [][] M = new int[votes.length+1][sum+1];

		for (int i = 1; i <= votes.length; i++) {
			int w_i = votes[i-1];
			for (int w = 0; w <=sum; w++) {
				if (w < w_i) {
					M[i][w]= M[i-1][w];
				}
				else {
					int choiceAddElement = votes[i-1] + M[i-1][w-w_i];
					int choiceIgnoreElement = M[i-1][w];
					if (choiceAddElement > choiceIgnoreElement) {
						M[i][w] = choiceAddElement;
					}
					else {
						M[i][w] = choiceIgnoreElement;
					}
				}
			}
		}	
		
		// M[votes.length][sum] = 269
		PathCount(M, votes, votes.length, sum);
		
		System.out.println(M[votes.length][sum]);
		System.out.println(path_count);
		System.out.println(bad_items);
		
//		printOptArray(M);
	}

	private static void printOptArray(int[][] M) {
		for (int i = 0; i < M.length; i++)
		{
			System.out.println("");
			for (int j = 0; j < M[i].length; j++)
			{
				System.out.print(M[i][j] + " ");
			}
		}
	}

}