triangle

Triangle.hs

import System.Environment (getArgs)

main = getArgs >>= (putStrLn . triangle . read . head)
  where
    triangle n = unlines $ map mkline $ [1..n]
    mkline i = unwords $ take i $ drop (i `mod` 2) $ altern
    altern = "0" : "1" : altern

Triangle.java

class Triangle {

  public static String mkline(int n) {
    StringBuilder line = new StringBuilder(Integer.toString(n % 2));
    for (int i = 1; i < n; i++)
      { line.append(" " + Integer.toString((n + i) % 2)); }
    return line.toString();
  }

  public static String mktriangle(int n) {
    StringBuilder triangle = new StringBuilder();
    for (int i = 1; i <= n; i++)
      { triangle.append(mkline(i) + "\n"); }
    return triangle.toString();
  }

  public static void main(String[] args) {
    System.out.print(mktriangle(Integer.parseInt(args[0])));
  }
}