- if (nn.is_even()) {
- int n = nn.div(_num2()).to_int();
- if (n <= highest_evenresult) {
- return evenresults[n];
- }
- if (evenresults.capacity() < (unsigned)(n+1)) {
- evenresults.reserve(n+1);
- }
- if (highest_evenresult < 0) {
- evenresults.push_back(_num1());
- highest_evenresult=0;
- }
- for (int i=highest_evenresult+1; i<=n; i++) {
- evenresults.push_back(numeric(evenresults[i-1].mul(numeric(i*2))));
- }
- highest_evenresult=n;
- return evenresults[n];
- } else {
- int n = nn.sub(_num1()).div(_num2()).to_int();
- if (n <= highest_oddresult) {
- return oddresults[n];
- }
- if (oddresults.capacity() < (unsigned)n) {
- oddresults.reserve(n+1);
- }
- if (highest_oddresult < 0) {
- oddresults.push_back(_num1());
- highest_oddresult=0;
- }
- for (int i=highest_oddresult+1; i<=n; i++) {
- oddresults.push_back(numeric(oddresults[i-1].mul(numeric(i*2+1))));
- }
- highest_oddresult=n;
- return oddresults[n];
- }