题目大意:给一个数n,统计n的阶乘中各个数字出现的次数。用java的大数做。
import java.io.*;
import java.util.*;
import java.math.*; class Main
{
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
BigInteger[] fact = new BigInteger[370];
fact[0] = BigInteger.valueOf(1);
for (int i = 1; i <= 366; i++)
fact[i] = fact[i-1].multiply(BigInteger.valueOf(i));
int[] cnt = new int[10];
int n;
while (sc.hasNext())
{
n = sc.nextInt();
if (n == 0) break;
BigInteger f = fact[n];
for (int i = 0; i < 10; i++) cnt[i] = 0;
while (f.compareTo(BigInteger.ZERO) > 0)
{
BigInteger r = f.mod(BigInteger.valueOf(10));
int idx = r.intValue();
cnt[idx]++;
f = f.divide(BigInteger.valueOf(10));
}
System.out.printf("%d! --\n", n);
System.out.printf(" (0)%5d (1)%5d (2)%5d (3)%5d (4)%5d\n", cnt[0], cnt[1], cnt[2], cnt[3], cnt[4]);
System.out.printf(" (5)%5d (6)%5d (7)%5d (8)%5d (9)%5d\n", cnt[5], cnt[6], cnt[7], cnt[8], cnt[9]);
}
}
}
一直不习惯java的输出,今天才发现c风格的printf函数,哈哈~