BinomialCoefficient.java

/*
 * Implementation of a dynamic programming table that contains binomial coefficients.
 *
 * Time complexity: O(N^2)
 */

package codebook.dp;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.StringTokenizer;

public class BinomialCoefficient {

  static BufferedReader br;
  static PrintWriter out;
  static StringTokenizer st;

  public static void main (String[] args) throws IOException {
    br = new BufferedReader(new InputStreamReader(System.in));
    out = new PrintWriter(new OutputStreamWriter(System.out));
    //br = new BufferedReader(new FileReader("in.txt"));
    //out = new PrintWriter(new FileWriter("out.txt"));

    int n = readInt();
    long[][] binomial = new long[n + 1][n + 1];
    for (int i = 0; i <= n; i++)
      for (int j = 0; j <= i; j++)
        binomial[i][j] = (j == 0 || i <= 1) ? 1 : binomial[i - 1][j - 1] + binomial[i - 1][j];

    out.close();
  }

  static String next () throws IOException {
    while (st == null || !st.hasMoreTokens())
      st = new StringTokenizer(br.readLine().trim());
    return st.nextToken();
  }

  static long readLong () throws IOException {
    return Long.parseLong(next());
  }

  static int readInt () throws IOException {
    return Integer.parseInt(next());
  }

  static double readDouble () throws IOException {
    return Double.parseDouble(next());
  }

  static char readCharacter () throws IOException {
    return next().charAt(0);
  }

  static String readLine () throws IOException {
    return br.readLine().trim();
  }
}