TopCoder: SRM 625 Div2 Round 1

AddMultiply.java

/**
 * TopCoder: SRM 625 Div2 Round 1
 * 
 * http://community.topcoder.com/stat?c=problem_statement&pm=13231&rd=15858&rm=322742&cr=20029384
 * 
 *  You are given an int y. We are looking for any int[] x that satisfies the following constraints:
 * 	- No x[i] can be equal to 0 or 1.
 * 	- Each x[i] must be between -1000 and 1000, inclusive.
 * 	- ( x[0] * x[1] ) + x[2] = y
 * 	- x has exactly three elements
 * 
 */
public class AddMultiply {
 
	/**
	 * @param y between 0 and 500, inclusive.
	 * @return int[] x has exactly three elements
	 */
	public int[] makeExpression(int y) {
 
		for (int x2 = -1000; x2 <=1000; x2++) {
			
			// No x[i] can be equal to 0 or 1.
			if(x2==0 || x2==1) {
				continue;
			}
			
			// ( x[0] * x[1] ) + x[2] = y
			int x0x1 = y-x2;
			
			// Each x[i] must be between -1000 and 1000, inclusive.
			for (int x0 = -1000; x0 <=1000; x0++) {
				
				if(x0==0 || x0==1) {
					continue;
				}
				
				// find x1 for gişven x0*x1 and x0
				int x1 = x0x1/x0;
				
				// Check if suitable
				if(x1*x2==x0x1 && x1!=0 && x1!=1 ) {
					int[] x = {x0,x1,x2};
					return x;
				}
			}
 
		}
 
		return null;
	}
 
}

AddMultiplyBest.java

public class AddMultiplyBest {
	public int[] makeExpression(int y) {
		int[] x = new int[3];
		if (y == 6 || y == 7) {
			x[0] = 2;
			x[1] = 2;
		} else {
			x[0] = 2;
			x[1] = 3;
		}

		x[2] = y - x[0] * x[1];

		return x;
	}
 
}