Anonymous user
Evaluate binomial coefficients: Difference between revisions
→{{header|Java}}: add more implementations, especially some reliable ones
(→{{header|Java}}: add more implementations, especially some reliable ones) |
|||
Line 1,126:
=={{header|Java}}==
<lang java>public class Binomial {
// precise, but may overflow and then produce completely incorrect results
private static long
{▼
if (k > n - k)
k = n - k;
long
for (int i
return
}
// same as above, but with overflow check
public static void main(String[] args)▼
private static Object binomialIntReliable(int n, int k) {
{▼
long binom = 1;
for (int i = 1; i <= k; i++) {
try {
binom = Math.multiplyExact(binom, n + 1 - i) / i;
} catch (ArithmeticException e) {
return "overflow";
}
▲ }
return binom;
}
}</lang>▼
// using floating point arithmetic, larger numbers can be calculated,
// but with reduced precision
▲ result *= (n - i + 1) / i;
double binom = 1.0;
for (int i = 1; i <= k; i++)
binom = binom * (n + 1 - i) / i;
return binom;
// slow, hard to read, but precise
private static BigInteger binomialBigInt(int n, int k) {
if (k > n - k)
k = n - k;
BigInteger binom = BigInteger.ONE;
for (int i = 1; i <= k; i++) {
binom = binom.multiply(BigInteger.valueOf(n + 1 - i));
binom = binom.divide(BigInteger.valueOf(i));
}
return
List<Object> data = Arrays.asList(
n,
k,
binomialInt(n, k),
binomialIntReliable(n, k),
binomialFloat(n, k),
binomialBigInt(n, k));
System.out.println(data.stream().map(Object::toString).collect(Collectors.joining("\t")));
}
public static void main(String[] args) {
demo(1000, 300);
}
▲}</lang>
{{Out}}
<pre>5 3 10 10 10.0
1000 300 -8357011479171942 overflow 5.428250046406143E263 542825004640614064815358503892902599588060075560435179852301016412253602009800031872232761420804306539976220810204913677796961128392686442868524741815732892024613137013599170443939815681313827516308854820419235457578544489551749630302863689773725905288736148678480</pre>
Recursive version, without overflow check:
<lang java>public class Binomial
| |||