ThreeSum.java in pgm

ThreeSum.java

public class ThreeSum

             {

    public static void printAll(int[] a)

{

        int N = a.length;

        for (int i = 0; i < N; i++)

{

            for (int j = i+1; j < N; j++)

{

                for (int k = j+1; k < N; k++)

{

                    if (a[i] + a[j] + a[k] == 0)

{

                        StdOut.println(a[i] + " " + a[j] + " " + a[k]);

                    }

                }

            }

        }

    }

              public static int count(int[] a)

             {

        int N = a.length;

        int cnt = 0;

        for (int i = 0; i < N; i++)

{

            for (int j = i+1; j < N; j++)

{

                for (int k = j+1; k < N; k++)

{

                    if (a[i] + a[j] + a[k] == 0)

 {

                        cnt++;

                    }

                }

            }

        }

        return cnt;

    }

    public static void main(String[] args) 

    {

        int N = StdIn.readInt();

        int[] a = new int[N];

        for (int i = 0; i < N; i++)

       {

            a[i] = StdIn.readInt();

        }

        Stopwatch timer = new Stopwatch();

        int cnt = count(a);

        StdOut.println("elapsed time = " + timer.elapsedTime());

        StdOut.println(cnt);

    }

}