生成“选择”组合的组合。操作 [英] Generating the combinations of a "choose" operation
问题描述
我要执行 6选择2操作的变体。我写了下面的代码。
I want to perform a variation of a "6 choose 2" operation. I have written the following code.
public void choosePatterns(){
String[] data = {"1", "2", "3", "4", "5", "6"};
String[] originalPattern = new String[15];
int index = 0;
for(int i = 0; i < (6-1); i++)
{
for(int j = i+1; j < 6; j++)
{
System.out.println(i + "," +j);
}
}
}
到目前为止,我的代码会全部生成 6选择2的可能组合。但是,我想改变这个并打印所有剩余的数字。到目前为止,如果 6选择2的组合之一是 3和 4,那么我想打印 1, 2, 5, 6。
My code so far generates all the possible combinations of "6 choose 2." However, I would like to vary this and print all the remaining numbers. So far instance, if one of the combinations of "6 choose 2" is "3" and "4," then I would like to print "1," "2," "5," "6."
我不确定如何最有效地做到这一点。漫长的方法是删除数据数组中的那些索引,移动数据以确保没有间隙,然后打印该数组。
I am not sure how to most efficiently do this. The long-winded way would be to delete those indices in the "data" array, shift the data so there aren't gaps, then print the array. But is there a faster, more efficient way to do this?
推荐答案
这是一种方法。
public static void choosePatterns(int total, int toChoose) {
List<Integer> indices = IntStream.range(1, toChoose + 1).mapToObj(i -> Integer.valueOf(0)).collect(Collectors.toList());
resetIndex(indices, 0, 1, total);
while (true) {
System.out.println("chosen: " + indices);
System.out.print("not chosen: ");
for (int i = 1; i <= total; i++) {
if (! indices.contains(Integer.valueOf(i))) {
System.out.print(i + " ");
}
}
System.out.println("\n");
if (! incrementIndices(indices, indices.size() - 1, total)) {
break;
}
}
}
public static boolean resetIndex(List<Integer> indices, int posn, int value, int total) {
if (value <= total) {
indices.set(posn, value);
return posn == indices.size() - 1 ? true : resetIndex(indices, posn + 1, value + 1, total);
} else {
return false;
}
}
public static boolean incrementIndices(List<Integer> indices, int posn, int total) {
if (indices.get(posn) < total) {
indices.set(posn, indices.get(posn) + 1);
} else {
int resetPosn = posn;
do {
if (resetPosn-- == 0) return false;
} while (! resetIndex(indices, resetPosn, indices.get(resetPosn) + 1, total));
}
return true;
}
public static void main(String[] args) throws IOException {
choosePatterns(6, 2);
}
打印以下内容:
chosen: [1, 2]
not chosen: 3 4 5 6
chosen: [1, 3]
not chosen: 2 4 5 6
chosen: [1, 4]
not chosen: 2 3 5 6
chosen: [1, 5]
not chosen: 2 3 4 6
chosen: [1, 6]
not chosen: 2 3 4 5
chosen: [2, 3]
not chosen: 1 4 5 6
chosen: [2, 4]
not chosen: 1 3 5 6
chosen: [2, 5]
not chosen: 1 3 4 6
chosen: [2, 6]
not chosen: 1 3 4 5
chosen: [3, 4]
not chosen: 1 2 5 6
chosen: [3, 5]
not chosen: 1 2 4 6
chosen: [3, 6]
not chosen: 1 2 4 5
chosen: [4, 5]
not chosen: 1 2 3 6
chosen: [4, 6]
not chosen: 1 2 3 5
chosen: [5, 6]
not chosen: 1 2 3 4
这篇关于生成“选择”组合的组合。操作的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!