int binary_search(int t[], int n, int v)
{
	int l=1, u=n;

	while (l<=u)
	{
		int m=(u+l)/2;

		if (v<t[m]) u=m-1;
		else if (v>t[m]) l=m+1;
		else return m;
	}
	return 0;
}