Count numbers in the range [L, R] having only three set bits

#include using namespace std;  void precompute(vector& v){        for (long long i = 0; i < 64; i++) {                for (long long j = i + 1; j < 64; j++) {                        for (long long k = j + 1; k < 64; k++) {                                                  long long int x                    = (1LL