unsigned long long bsts(unsigned n) {
if (n <= 1) {
return 1;
}
unsigned long long res = 0;
unsigned i;
for (i = 0; i < n; i++) {
res += bsts(i)*bsts(n-i-1);
}
return res;
}
bool
Val::
check()
{
vector<short>::const_iterator vsi = vec().begin();
Bsts::const_iterator bi = bsts().begin();
for( ; bi != bsts().end() ; bi++)
{
if((*bi)->num() < (*vsi)) return false;
vsi++;
}
return true;
}
int main(void) {
printf("Enter a positive integer to calculate the number of binary trees of size N\n"
"and the number of binary search trees of size N\n");
printf("> ");
unsigned n;
while (scanf("%u", &n) == 1) {
printf("Binary trees: %llu\nBinary search trees: %llu\n", trees(n), bsts(n));
printf("> ");
}
return 0;
}
