Solution to ACM programming problem with the test questions. To run this do (unix) $ javac Main.java && java Main

Main.java

/*
 * Max F
 * Run with 
 * $ javac Main.java && java Main
 *  90  (desired score)
 *  4   (num exams)
 *  25 25 25 25 (weight of each)
 *  80 80 80 (scores on each exam before final)
 *
 */
import java.io.*;

public class Main
{
    public static void main(String[] Args) throws Exception
    {
        //Set up io
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        //Read in the desired score
        int desired = Integer.parseInt(br.readLine());
        
        //Read in the number of tests in the class
        int numTests = Integer.parseInt(br.readLine());

        //Read in the weights
        String weights = br.readLine();
        String[] weights_ary = weights.split(" ");
        int[] int_weights = new int[numTests];
        for(int i = 0; i < numTests; i++){
            int_weights[i] = Integer.parseInt(weights_ary[i]);
        }

        //Read in the actual scores
        String scores = br.readLine();
        String[] scores_ary = scores.split(" ");
        int[] int_scores = new int[numTests];
        for(int i = 0; i < numTests - 1; i++){
            int_scores[i] = Integer.parseInt(scores_ary[i]);
        }

        float weighted_avg = 0;
        for(int i = 0; i < numTests - 1; i++){
            weighted_avg += ((float)int_weights[i] / 100.0 * (float)int_scores[i]);
        }

        if(weighted_avg + (int_weights[numTests - 1]) >= desired){
            System.out.println(String.format("Score achieved\nYou need a %f", (desired - weighted_avg) / (float)int_weights[numTests - 1] * 100 ));
        }else{
            System.out.println("Can not achieve score.");
        }
    }
}