题解 | 【模板】整数域二分

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int n, q;
    cin >> n >> q;
    vector<long long> a(n);
    for (int i = 0; i < n; ++i) {
        cin >> a[i];
    }
    sort(a.begin(), a.end());
    
    while (q--) {
        long long l, r;
        cin >> l >> r;
        auto left = lower_bound(a.begin(), a.end(), l);
        auto right = upper_bound(a.begin(), a.end(), r);
        cout << (right - left) << '\n';
    }

    return 0;
}