3、樗蒲(chp.cpp)編程，看看編編

using std::cout;

using std::endl;

using std::cin;

#include <vector>

using std::vector;

int main() {

int n, s, t, c = 0;

cin >> n >> s;

vector<int> ints;

while (cin >> t) ints.push_back(t);

for (vector<int>::iterator i = ints.begin(); i != ints.end(); ++i)

for (vector<int>::iterator j = i + 1; j != ints.end(); ++j)

if (*i + *j <= s) ++c;

cout << c << endl;

return 0;

}