Бинарный поиск (классика)

#include <iostream>
#include <string>
#include <cmath>
using namespace std;

int main()
{
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);

	int n, k, c, l, r, m;
	cin >> n;
	int* mas = new int[n];
	for (int i = 0; i < n; i++)
	{
		cin >> mas[i];
	}
	cin >> k;

	for (int s = 0; s < k; s++)
	{
		l = 0;
		r = n - 1;
		cin >> c;


		while (l - r < 0)
		{
			m = (l + r + 1) / 2;
			if (mas[m] <= c)
			{
				l = m;
			}
			else
			{
				r = m - 1;
			}
		}
		if (mas[l] == c)
		{
			cout << l + 1 << " ";
		}
		else
		{
			cout << -1 << " ";
		}
	}


}