/**
 * Implements a brute force solution to the transformed subset sum problem
 * @author alchambers
 *
 */
public class BruteForceTransform implements StockIfc{
	
	public StockInfo solve(int[] prices){
		int numDays = prices.length;		
		int[] change = new int[numDays-1];
		
		// Transform the problem into an instance of the
		// Maximum subarray problem
		for(int i = 0; i < change.length; i++) {
			change[i] = prices[i+1]-prices[i];
		}
		
		return bruteForce(change);		
	}
	
	/**
	 * Considers all possible combinations
	 * @param array An array of integers
	 * @return solution to the transformed Stock Market problem
	 */
	private StockInfo bruteForce(int[] array) {
		StockInfo s = new StockInfo();
		
		int best = Integer.MIN_VALUE;
		for(int start = 0; start < array.length; start++){
			int sum = 0;
			for(int i = start; i < array.length; i++){
				sum += array[i];
				if(sum > best){
					best = sum;
					s.buy_index = start;
					s.sell_index = i;
					s.profit = sum;
				}				
			}
		}
		return s;
	}	
}