SUB perms (n)
    DIM p((n + 1) * 4)
    FOR i = 1 TO n
    p(i) = -i
    NEXT i
    s = 1

    DO
    PRINT "Perm: (";
    FOR i = 1 TO n
        PRINT ABS(p(i)); "";
    NEXT i
    PRINT ") Sign: "; s

    k = 0
    FOR i = 2 TO n
        IF p(i) < 0 AND (ABS(p(i)) > ABS(p(i - 1))) AND (ABS(p(i)) > ABS(p(k))) THEN k = i
    NEXT i
    FOR i = 1 TO n - 1
        IF p(i) > 0 AND (ABS(p(i)) > ABS(p(i + 1))) AND (ABS(p(i)) > ABS(p(k))) THEN k = i
    NEXT i
    IF k THEN
        FOR i = 1 TO n    'reverse elements > k
        IF ABS(p(i)) > ABS(p(k)) THEN p(i) = -p(i)
        NEXT i
        'if p(k) < 0 then i = k-1 else i = k+1
        i = k + SGN(p(k))
        SWAP p(k), p(i)
        'temp = p(k)
        'p(k) = p(i)
        'p(i) = temp
        s = -s
    END IF
    LOOP UNTIL k = 0
END SUB

perms (3)
PRINT
perms (4)