我能够在C.中实现静态数组数的笛卡尔积.但是我想构建一个动态地获取输入数组的代码.有人可以解释一下如何“只使用数组”.如果不可能的话有阵列请告诉我其他解决方案.谢谢.这是我的代码,下面是3个阵列的笛卡尔积.
#include<stdio.h>
int main(void)
{
int array1[100];
int array2[100];
int array3[100];
int cartesian_array[100][100];
int m,n,o;
int i,j;
int p=0,q=0,r=0;
int x,y,z;
int cartesian_arr_row_len;
int cartesian_arr_col_len;
printf("Enter the size of first array:\n");
scanf("%d",&m);
printf("Enter the size of second array:\n");
scanf("%d",&n);
printf("Enter the size of third array:\n");
scanf("%d",&o);
printf("Enter the first array elements:\n");
for(i=0;i<m;i++)
scanf("%d",&array1[i]);
printf("Enter the second array elements:");
for(i=0;i<n;i++)
scanf("%d",&array2[i]);
printf("Enter the third array elements:");
for(i=0;i<o;i++)
scanf("%d",&array3[i]);
cartesian_arr_row_len=m*n*o;
cartesian_arr_col_len=3;
x=cartesian_arr_row_len/m;
y=cartesian_arr_row_len/(m*n);
z=o;
for(i=0;i<cartesian_arr_row_len;i++)
{
for(j=0;j<cartesian_arr_col_len;j++)
{
if(j==0)
{
cartesian_array[i][j]=array1[p/x];
p++;
}
if(j==1)
{
cartesian_array[i][j]=array2[q/y];
q++;
if(q>=n*y)
q=0;
}
if(j==2)
{
cartesian_array[i][j]=array3[r%z];
r++;
}
}
}
printf("The Cartesian Product of two arrays is:\n");
for(i=0;i<cartesian_arr_row_len;i++)
{
for(j=0;j<cartesian_arr_col_len;j++)
{
printf("%d\t",cartesian_array[i][j]);
}
printf("\n");
}
return 0;
}
最佳答案 你能阅读Java代码并自己翻译吗？
import java.util.*;
class CartesianIterator <T> implements Iterator <List <T>> {
private final List <List <T>> lilio;
private int current = 0;
private final long last;
public CartesianIterator (final List <List <T>> llo) {
lilio = llo;
long product = 1L;
for (List <T> lio: lilio)
product *= lio.size ();
last = product;
}
public boolean hasNext () {
return current != last;
}
public List <T> next () {
++current;
return get (current - 1, lilio);
}
public void remove () {
++current;
}
private List<T> get (final int n, final List <List <T>> lili) {
switch (lili.size ())
{
case 0: return new ArrayList <T> (); // no break past return;
default: {
List <T> inner = lili.get (0);
List <T> lo = new ArrayList <T> ();
lo.add (inner.get (n % inner.size ()));
lo.addAll (get (n / inner.size (), lili.subList (1, lili.size ())));
return lo;
}
}
}
}
class CartesianIterable <T> implements Iterable <List <T>> {
private List <List <T>> lilio;
public CartesianIterable (List <List <T>> llo) {
lilio = llo;
}
public Iterator <List <T>> iterator () {
return new CartesianIterator <T> (lilio);
}
}
class CartesianIteratorTest {
public static void main (String[] args) {
List <Character> la = Arrays.asList (new Character [] {'a', 'b'});
List <Character> lb = Arrays.asList (new Character [] {'b', 'c'});
List <Character> lc = Arrays.asList (new Character [] {'c', 'a'});
List <List <Character>> llc = new ArrayList <List <Character>> ();
llc.add (la);
llc.add (lb);
llc.add (lc);
CartesianIterable <Character> ci = new CartesianIterable <Character> (llc);
for (List<Character> lo: ci)
show (lo);
la = Arrays.asList (new Character [] {'x', 'y', 'z'});
lb = Arrays.asList (new Character [] {'b'});
lc = Arrays.asList (new Character [] {'c'});
llc = new ArrayList <List <Character>> ();
llc.add (la);
llc.add (lb);
llc.add (lc);
ci = new CartesianIterable <Character> (llc);
for (List<Character> lo: ci)
show (lo);
}
public static void show (List <Character> lo) {
System.out.print ("(");
for (Object o: lo)
System.out.print (o);
System.out.println (")");
}
}
我不知道C中是否存在与迭代器类似的东西.迭代很可能对你没用.
代码的想法是,有一个计数器,它在结果集的所有元素上创建一个索引,并计算绑定到该值的元素.
如果我们有3组(1,2,3)(4,5)(6,7,8),我们有18 = 3x2x3的结果.我们可以,例如迭代器位置7计算结果如下：
7 % 3 = 1 => (1,2,3)[1] = 2 (number modulo 1st group size)
7 / 3 = 2 (int division) (number div 1st group size)
2 % 2 = 0 => (4,5)[0] = 4 (rest modulo 2nd group size)
2 / 2 = 0
0 % 3 = 0 => (7,8,9) => 7
idx g1 g2 g3
0 1 4 6
1 2 4 6
2 3 4 6
3 1 5 6
4 2 5 6
5 3 5 6
6 1 4 7
7 2 4 7
8 3 4 7
9 1 5 7
10 2 5 7
11 3 5 7
12 1 4 8
13 2 4 8
14 3 4 8
15 1 5 8
16 2 5 8
17 3 5 8
