过了样例，其余全WA，请问是哪个细节上出了问题，请大佬指点。

#include <iostream>
#include <cstring>
#include <algorithm>

using namespace std;
const int N = 2e5 + 10;
int a[N];
int n, target;

int main()
{
    cin >> n >> target;
    for (int i=1; i <= n; i ++)
        cin >> a[i];
    int cnt=0;
    for (int i=1; i <= n; i ++)
    {
        int sum = target + a[i];
        //在序列a中二分查找该元素！
        int l = 1, r = n;
        while (l < r)
        {
            int mid = l + r >> 1;
            if (a[mid] >= sum) r = mid;
            else l = mid + 1;
        }
        if (a[r] == sum) cnt ++;
    }
    cout << cnt << endl;
    return 0;
}