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  1. /* package whatever; // don't place package name! */
  2.  
  3. import java.util.*;
  4. import java.lang.*;
  5. import java.io.*;
  6.  
  7. /* Name of the class has to be "Main" only if the class is public. */
  8. class Ideone
  9. {
  10.    static int[] occurrences;
  11.    static int[] target;
  12.  
  13.    static void bruteForce()
  14.    {
  15.       occurrences = new int[10];
  16.       target = new int[10];
  17.       for (int i = 0; i < 10; i++)
  18.          occurrences[i] = 1;
  19.  
  20.       bruteForce(0);
  21.    }
  22.  
  23.  
  24.    static boolean bruteForce(int value)
  25.    {
  26.       if (value > 9)
  27.       {
  28.          for (int i = 0; i < 10; i++)
  29.             if (occurrences[i] != target[i])
  30.                return false;
  31.          System.out.println(Arrays.toString(target));
  32.          return true;
  33.       }
  34.       for (int i = 1; i < 10; i++)
  35.       {
  36.         target[value] = i;
  37.         // fail early - not strictly necessary, but should help running time
  38.         if (value >= i && occurrences[i] + 1 > target[i])
  39.           continue;
  40.         occurrences[i]++;
  41.  
  42.         // recurse
  43.         if (bruteForce(value + 1))
  44.            return true;
  45.  
  46.         occurrences[i]--;
  47.       }
  48.       return false;
  49.    }
  50.  
  51.    public static void main(String[] args)
  52.    {
  53.       bruteForce();
  54.    }
  55. }
Success #stdin #stdout 2.72s 380160KB
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stdin
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Standard input is empty
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[1, 7, 3, 2, 1, 1, 1, 2, 1, 1]
https://ideone.com/H0G37i
language:
Java (12.0.1)
created:
11 years ago
visibility:
public

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