TLE in counting pairs problem

[abhstract1410]

This is the code that I have written in response to the counting pairs problem but it is giving tle. Could anyone please point out the reason? Thanks

#include <bits/stdc++.h>
#define ll long long
#define fo(i, a, n) for (int i = a; i < n; ++i)
#define whi(t) \
    int t;     \
    cin >> t;  \
    while (t--)
#define vi(v) vector<ll int> v
using namespace std;
int b_search(int l, int k, vector<ll int> A)
{
    ll int high = A.size() - 1, mid, low = l + 1;
    //cout << A[low] << endl;

    while (low <= high)
    {
        mid = (low + high) / 2;
        if (A[mid] == k)
        {
            return 1;
        }
        else if (A[mid] < k)
        {
            low = mid + 1;
        }
        else
            high = mid - 1;
        //cout << A[mid] << "*" << A[low] << " " << A[high] << "\n";
    }

    return 0;
}
int main()
{
    ios::sync_with_stdio(false);
    ll int n, k, count;
    cin >> n >> k;
    vi(A)(n, 0);
    for (int i = 0; i < n; ++i)
    {
        cin >> A[i];
    }

    count = 0;
    sort(A.begin(), A.end());
    for (int i = 0; i < n - 1; ++i)
    {
        count += b_search(i, k + A[i], A);
    }

    cout << count;
}

[simes]

This is PAIRS1, in case any readers are wondering which of the “counting pairs” problems this is.

I can’t answer your question, but I can make a couple of observations:

1. I believe a static array would be quicker than using a vector.
2. All integers fit into 32 bits, so why use 64 bit integers? It’s slower to manipulate 8 bytes than 4. (On 32 bit machines anyway.)

I’m not C++ programmer and haven’t solved this problem, so take into consideration that I may not know what I’m talking about.