1 files changed, 65 insertions, 0 deletions
diff --git a/Semestr 4/ask/lista11/gen.py b/Semestr 4/ask/lista11/gen.py
new file mode 100644
index 0000000..d4de762
--- /dev/null
+++ b/Semestr 4/ask/lista11/gen.py
@@ -0,0 +1,65 @@
+def next_permutation(a):
+  """Generate the lexicographically next permutation inplace.
+
+  https://en.wikipedia.org/wiki/Permutation#Generation_in_lexicographic_order
+  Return false if there is no next permutation.
+  """
+  # Find the largest index i such that a[i] < a[i + 1]. If no such
+  # index exists, the permutation is the last permutation
+  for i in reversed(range(len(a) - 1)):
+      if a[i] < a[i + 1]:
+          break  # found
+  else:  # no break: not found
+      return False  # no next permutation
+
+  # Find the largest index j greater than i such that a[i] < a[j]
+  j = next(j for j in reversed(range(i + 1, len(a))) if a[i] < a[j])
+
+  # Swap the value of a[i] with that of a[j]
+  a[i], a[j] = a[j], a[i]
+
+  # Reverse sequence from a[i + 1] up to and including the final element a[n]
+  a[i + 1:] = reversed(a[i + 1:])
+  return True
+
+def perm_to_str(a):
+  return ''.join(map(str, a))
+
+def str_to_perm(s):
+  return [int(c) for c in s]
+
+t = [0,1,2,3]
+perm_to_idx = dict()
+
+def bbin(x):
+  return bin(x)[2:]
+
+cnt = 23
+while True:
+  perm_to_idx[perm_to_str(t)] = cnt
+  cnt -= 1
+  if not next_permutation(t):
+    break
+
+for p in perm_to_idx.keys():
+  for i in range(4):
+    t = str_to_perm(p)
+    for j in range(4):
+      if t[j] > t[i]:
+        t[j] -= 1
+    t[i] = 3
+    print(p, 'x', i, '->', perm_to_str(t), ':\t', bbin(perm_to_idx[p]), '\t', bbin(i), '\t', bbin(perm_to_idx[perm_to_str(t)]), end='\t')
+    print(perm_to_idx[p], '\t', i, '\t', perm_to_idx[perm_to_str(t)])
+
+print('\n-----\n')
+
+
+for p in perm_to_idx.keys():
+  for i in range(4):
+    t = str_to_perm(p)
+    for j in range(4):
+      if t[j] > t[i]:
+        t[j] -= 1
+    t[i] = 3
+    print(p, 'x', i, '->', perm_to_str(t), ':\t', bbin(perm_to_idx[p]), '\t', bbin(i), '\t', bbin(perm_to_idx[perm_to_str(t)]), end='\t')
+    print(perm_to_idx[p], '\t', i, '\t', perm_to_idx[perm_to_str(t)])