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  1. import java.util.Arrays;
  2.  
  3. class Graph26 {
  4.     private static final int A = 0;
  5.     private static final int B = 1;
  6.     private static final int C = 2;
  7.     private static final int D = 3;
  8.     private static final int E = 4;
  9.     private static final int F = 5;
  10.     private static final int G = 6;
  11.  
  12.     private final static boolean rule1(final int[] n) {
  13.         return n[A] != 2;
  14.     }
  15.  
  16.     private final static boolean rule2(final int[] n) {
  17.         return n[A] + n[B]  == n[F];
  18.     }
  19.  
  20.     private final static boolean rule3(final int[] n) {
  21.         return n[C] - n[D]  == n[G];
  22.     }
  23.  
  24.     private final static boolean rule4(final int[] n) {
  25.         return n[D] + n[E] == 2*n[F];
  26.     }
  27.  
  28.     private final static boolean rule5(final int[] n) {
  29.         return n[E] + n[G]  == n[F];
  30.     }
  31.  
  32.  
  33.     private final static boolean isValid(final int[] nodes) {
  34.         return rule1(nodes) && rule2(nodes) && rule3(nodes) && rule4(nodes)
  35.                 && rule5(nodes);
  36.     }
  37.  
  38.     class Permutation {
  39.         private final int[] o;
  40.         private boolean perms = true;
  41.  
  42.         public boolean hasPerms() {
  43.             return perms;
  44.         }
  45.  
  46.         Permutation(final int[] obj) {
  47.             o = obj.clone();
  48.         }
  49.  
  50.         private int[] nextPerm() {
  51.             int temp;
  52.             int j = o.length - 2;
  53.             while (o[j] > o[j + 1]) {
  54.             j--;
  55.             if (j < 0) {
  56.             perms = false;
  57.             break;
  58.             }
  59.             }
  60.             if (perms) {
  61.             int k = o.length - 1;
  62.             while (o[j] > o[k]) {
  63.             k--;
  64.             }
  65.             temp = o[k];
  66.             o[k] = o[j];
  67.             o[j] = temp;
  68.             int r = o.length - 1;
  69.             int s = j + 1;
  70.             while (r > s) {
  71.             temp = o[s];
  72.             o[s] = o[r];
  73.             o[r] = temp;
  74.             r--;
  75.             s++;
  76.             }
  77.             }
  78.             return o.clone();
  79.         }
  80.     }
  81.  
  82.     public static void main(final String[] args) {
  83.         int[] nodes = new int[] { 1, 2, 3, 4, 5, 6, 7};
  84.         final Graph26 graph = new Graph26();
  85.         final Permutation p = graph.new Permutation(nodes);
  86.         int i = 0;
  87.         while (p.hasPerms()) {
  88.         if (isValid(nodes)) {
  89.         System.out.println(Arrays.toString(nodes));
  90.         }
  91.         i++;
  92.         nodes = p.nextPerm();
  93.         }
  94.         System.out.println(i);
  95.     }
  96. }
  97.  
Success #stdin #stdout 0.04s 213440KB
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Standard input is empty
stdout
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[3, 2, 7, 6, 4, 5, 1]
5040
https://ideone.com/wwxG0
language:
Java (HotSpot 12)
created:
13 years ago
visibility:
public

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