Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>As I understand it, you are effectively asking for ways of partitioning the interval [100,199] into 10 parts, i.e. you want to find numbers x[0], ..., x[10] such that:</p> <pre><code>x[0] = 100 &lt; x[1] &lt; x[2] &lt; ... &lt; x[9] &lt; x[10] = 199 </code></pre> <p>Define a recursive function <code>partition(intervalSize, pieces)</code> which counts the number of ways to partition a given interval. You are after <code>partition(100, 10)</code>.</p> <p>The following Java code counts the partitions (sorry, don't know PHP that well):</p> <pre><code>public class Partitions { static long[][] partitions = new long[100][10]; private static long partition(int intervalSize, int pieces) { if (partitions[intervalSize-1][pieces-1] != 0) { return partitions[intervalSize-1][pieces-1]; } long partition = 0L; if (pieces == 1) { partition = 1L; } else { for (int i = 1; i &lt;= intervalSize - 1; i++) { partition += partition(intervalSize - i, pieces - 1); } } partitions[intervalSize-1][pieces-1] = partition; return partition; } public static void main(String[] args) { System.out.println(partition(100, 10)); } } </code></pre> <p>The following Java code prints out the actual partitions. Because the number of partitions is so high for (100,10), I'm illustrating the answer for (5,3):</p> <pre><code>public class Partitions2 { private static void showPartitions(int sizeSet, int numPartitions) { showPartitions("", 0, sizeSet, numPartitions); } private static void showPartitions(String prefix, int start, int finish, int numLeft) { if (numLeft == 0 &amp;&amp; start == finish) { System.out.println(prefix); } else { prefix += "|"; for (int i = start + 1; i &lt;= finish; i++) { prefix += i + ","; showPartitions(prefix, i, finish, numLeft - 1); } } } public static void main(String[] args) { showPartitions(5, 3); } } </code></pre> <p>The output is:</p> <pre> |1,|2,|3,4,5, |1,|2,3,|4,5, |1,|2,3,4,|5, |1,2,|3,|4,5, |1,2,|3,4,|5, |1,2,3,|4,|5, </pre>
    singulars
    1. This table or related slice is empty.
    1. POCombinatorics: Building 10 groups of 100 elements while elements remain sorted
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USSimon Nickerson
    1. USSimon Nickerson
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POCombinatorics: Building 10 groups of 100 elements while elements remain sorted
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COThank you! This should be your code in PHP: http://paste.bradleygill.com/index.php?paste_id=15709 Unfortunately, it takes a very long time (>30sec) or runs infinitely. Is there a mistake anywhere in the code? Maybe you can compare your code with the code Juliet linked to?
      singulars
      1. PO
      1. UScaw
    2. COIt's a recursive function which will get much faster if you memoize (i.e. remember values of the function you've already computed).
      singulars
      1. PO
      1. USSimon Nickerson
    3. CO@marco92w: Java code I've just added terminates in under a second
      singulars
      1. PO
      1. USSimon Nickerson
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload