Hofstadter Figure-Figure sequences: Difference between revisions

=={{header|C++}}==

{{works with|C++|11}}

{{trans|Java}}

<lang cpp>#include <iostream>

#include <set>

#include <vector>

using namespace std;

unsigned hofstadter(unsigned rlistSize, unsigned slistSize)

{

auto rlist = new vector<unsigned> { 1, 3, 7 };

auto slist = new vector<unsigned> { 2, 4, 5, 6 };

auto list = rlistSize > 0 ? rlist : slist;

auto n = rlistSize > 0 ? rlistSize : slistSize;

while (list->size() > n) list->pop_back();

while (list->size() < n)

{

auto lastIndex = rlist->size() - 1;

auto lastr = (*rlist)[lastIndex];

auto r = lastr + (*slist)[lastIndex];

rlist->push_back(r);

for (auto s = lastr + 1; s < r && list->size() < n;)

slist->push_back(s++);

}

return (*list)[n - 1];

}

int main()

{

cout << "R():";

for (auto n = 1; n <= 10; n++) cout << " " << hofstadter(n, 0);

cout << endl;

set<unsigned> r, s;

for (auto n = 1; n <= 960; n++)

{

if (n <= 40)

r.insert(hofstadter(n, 0));

s.insert(hofstadter(0, n));

}

for (auto n = 1; n <= 1000; n++)

if (r.count(n) == s.count(n))

clog << "integer " << n << " either in both or neither set" << endl;

cout << "done" << endl;

return 0;

}</lang>

{{out}}

As Java.