public BigInt sqrt()
{
if (less(this, ZERO))
{
throw new ArgumentException("BigNumber must be >=0");
}
int pos = (number.Length + 1) / 2;
BigInt cur = new BigInt(pos, false);
pos--;
while (pos >= 0)
{
int l = 0, r = BASE;
int curDigit = 0;
while (l <= r) // подбираем текущую цифру
{
int m = (l + r) >> 1;
cur.number[pos] = m;
if (BigInt.lessEqualAbs(BigInt.multiply(cur, cur), this))
{
curDigit = m;
l = m + 1;
}
else
{
r = m - 1;
}
}
cur.number[pos] = curDigit;
pos--;
}
Array.Copy(cur.number, 0, this.number, 0, cur.number.Length);
return(this);
}