-
Notifications
You must be signed in to change notification settings - Fork 0
/
Problem53.java
38 lines (33 loc) · 1.02 KB
/
Problem53.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
/*
* Prompt: How many, not necessarily distinct, values of nCr, for 1 ≤ n ≤ 100, are greater than one-million?
*
* Execute: javac Problem53.java; java Problem53; rm Problem53.class
*
* Answer: 4075
*/
import java.math.BigInteger;
public class Problem53 {
public static BigInteger[] factorials = new BigInteger[101];
public static void main(String[] args) {
BigInteger limit = BigInteger.valueOf(1000000);
// Calculate factorials from 0-100
factorials[0] = BigInteger.valueOf(1);
for (int i = 1; i <= 100; i++) {
factorials[i] = factorials[i - 1].multiply(BigInteger.valueOf(i));
}
int count = 0;
for (int i = 1; i <= 100; i++) {
for (int j = i; j > 0; j--) {
if (c(i, j).compareTo(limit) > 0) {
count++;
}
}
}
System.out.println(count);
}
public static BigInteger c(int n, int r) {
BigInteger numerator = factorials[n];
BigInteger denominator = factorials[r].multiply(factorials[n - r]);
return numerator.divide(denominator);
}
}