}

  // Depends on the correctness of BigIntegerMath.binomial.
  public void testBinomial() {
    for (int n = 0; n <= 70; n++) {
      for (int k = 0; k <= n; k++) {
        BigInteger expectedBig = BigIntegerMath.binomial(n, k);
        long expectedLong = fitsInLong(expectedBig) ? expectedBig.longValue() : Long.MAX_VALUE;
        assertEquals(expectedLong, LongMath.binomial(n, k));
      }
    }
  }

  }

  // Depends on the correctness of BigIntegerMath.binomial.
  public void testBinomial() {
    for (int n = 0; n <= 70; n++) {
      for (int k = 0; k <= n; k++) {
        BigInteger expectedBig = BigIntegerMath.binomial(n, k);
        long expectedLong = fitsInLong(expectedBig) ? expectedBig.longValue() : Long.MAX_VALUE;
        assertEquals(expectedLong, LongMath.binomial(n, k));
      }
    }
  }

            .size());

    // Almost force an overflow in the binomial coefficient calculation
    assertEquals(
        1391975640 /*C(34,14)*/,
        Collections2.orderedPermutations(concat(nCopies(20, 1), nCopies(14, 2))).size());
    // Do force an overflow in the binomial coefficient calculation
    assertEquals(
        Integer.MAX_VALUE,

        assertEquals(expected, BigIntegerMath.binomial(n, k));
      }
    }
  }

  public void testBinomialOutside() {
    for (int n = 0; n <= 50; n++) {
      try {
        BigIntegerMath.binomial(n, -1);
        fail("Expected IllegalArgumentException");
      } catch (IllegalArgumentException expected) {
      }
      try {
        BigIntegerMath.binomial(n, n + 1);

          permutations = IntMath.saturatedMultiply(permutations, IntMath.binomial(n, r));
          r = 0;
          if (permutations == Integer.MAX_VALUE) {
            return Integer.MAX_VALUE;
          }
        }
        n++;
        r++;
      }
      return IntMath.saturatedMultiply(permutations, IntMath.binomial(n, r));
    }

    @Override
    public int size() {
      return size;

          permutations = IntMath.saturatedMultiply(permutations, IntMath.binomial(n, r));
          r = 0;
          if (permutations == Integer.MAX_VALUE) {
            return Integer.MAX_VALUE;
          }
        }
        n++;
        r++;
      }
      return IntMath.saturatedMultiply(permutations, IntMath.binomial(n, r));
    }

    @Override
    public int size() {
      return size;

	neg := false
	if a < 0 {
		neg = (b-a)&1 == 0
		a, b = -b, -a
	}

	z.abs = z.abs.mulRange(uint64(a), uint64(b))
	z.neg = neg
	return z
}

// Binomial sets z to the binomial coefficient C(n, k) and returns z.
func (z *Int) Binomial(n, k int64) *Int {
	if k > n {
		return z.SetInt64(0)
	}
	// reduce the number of multiplications by reducing k
	if k > n-k {
		k = n - k // C(n, k) == C(n, n-k)
	}

			// With 100 trials and profile fraction of 2, we expect to capture
			// 50 samples. Allow the test to pass if we get at least 20 samples;
			// the CDF of the binomial distribution says there's less than a
			// 1e-9 chance of that, which is an acceptably low flakiness rate.
			const samplingSlop = 2.5