1.8 KiB
id, title, challengeType, forumTopicId, dashedName
id | title | challengeType | forumTopicId | dashedName |
---|---|---|---|---|
5900f3d61000cf542c50fee7 | Problem 103: Special subset sums: optimum | 5 | 301727 | problem-103-special-subset-sums-optimum |
--description--
Let S(A)
represent the sum of elements in set A of size n. We shall call it a special sum set if for any two non-empty disjoint subsets, B and C, the following properties are true:
S(B) ≠ S(C)
; that is, sums of subsets cannot be equal.- If B contains more elements than C then
S(B) > S(C)
.
If S(A)
is minimised for a given n, we shall call it an optimum special sum set. The first five optimum special sum sets are given below.
\begin{align} & n = 1: \\{1\\} \\\\ & n = 2: \\{1, 2\\} \\\\ & n = 3: \\{2, 3, 4\\} \\\\ & n = 4: \\{3, 5, 6, 7\\} \\\\ & n = 5: \\{6, 9, 11, 12, 13\\} \\\\ \end{align}
It seems that for a given optimum set, A = \\{a_1, a_2, \ldots, a_n\\}
, the next optimum set is of the form B = \\{b, a_1 + b, a_2 + b, \ldots, a_n + b\\}
, where b is the "middle" element on the previous row.
By applying this "rule" we would expect the optimum set for n = 6
to be A = \\{11, 17, 20, 22, 23, 24\\}
, with S(A) = 117
. However, this is not the optimum set, as we have merely applied an algorithm to provide a near optimum set. The optimum set for n = 6
is A = \\{11, 18, 19, 20, 22, 25\\}
, with S(A) = 115
and corresponding set string: 111819202225
.
Given that A is an optimum special sum set for n = 7
, find its set string.
Note: This problem is related to Problem 105 and Problem 106.
--hints--
optimumSpecialSumSet()
should return the string 20313839404245
.
assert.strictEqual(optimumSpecialSumSet(), '20313839404245');
--seed--
--seed-contents--
function optimumSpecialSumSet() {
return true;
}
optimumSpecialSumSet();
--solutions--
// solution required