Permutationen IV

Permutations2.om

PROCEDURE GenPermutations(k, n: INTEGER; perm: Permutation); (* perm[n-k..n-1] is fixed except that those of perm[n-k+1..n-1] are to be incremented by 1 which are greater or equal to perm[n-k]; generate all variants for perm[0..n-k-1] *) VAR inserted: INTEGER; i: INTEGER; BEGIN IF k > 1 THEN inserted := perm[n-k]; i := n-k+1; WHILE i < n DO IF perm[i] >= inserted THEN INC(perm[i]); END; INC(i); END; END; IF k = n THEN GenPermutation(perm, n); ELSE i := 1; WHILE i <= k+1 DO perm[n-k-1] := i; GenPermutations(k + 1, n, perm); INC(i); END; END; END GenPermutations;