public static LargeNumberCustom Multiply(LargeNumberCustom x, LargeNumberCustom y)
{
if (IsZero(x) || IsZero(y))
{
return(0);
}
LargeNumberCustom result = new LargeNumberCustom();
int maxDigits = Math.Min(y._digits.Count, MAX_DIGITS);
for (int i = 0; i < maxDigits; i++)
{
byte yDigit = y._digits[y._digits.Count - i - 1];
if (yDigit != 0)
{
LargeNumberCustom partialProd = MultiplyByOneDigit(x, yDigit);
for (int j = 0; j < i; j++)
{
partialProd._digits.Add(0);
}
result = AddPositives(result, partialProd);
}
}
result._sign = x._sign * y._sign;
return(result);
}
public static LargeNumberCustom AddPositives(LargeNumberCustom x, LargeNumberCustom y)
{
LargeNumberCustom result = new LargeNumberCustom();
int maxDigits = Math.Max(x._digits.Count, y._digits.Count);
maxDigits = Math.Min(maxDigits, MAX_DIGITS);
result._digits = new List <byte>(maxDigits + 1);
int carry = 0;
for (int i = 0; i < maxDigits; i++)
{
int digitSum = carry;
if (x._digits.Count - 1 - i >= 0)
{
digitSum += x._digits[x._digits.Count - 1 - i];
}
if (y._digits.Count - 1 - i >= 0)
{
digitSum += y._digits[y._digits.Count - 1 - i];
}
result._digits.Insert(0, (byte)(digitSum % 10));
carry = digitSum / 10;
}
if (carry > 0)
{
result._digits.Insert(0, (byte)carry);
}
return(result);
}
private static LargeNumberCustom MultiplyByOneDigit(LargeNumberCustom x, byte y)
{
if (IsZero(x) || y == 0)
{
return(0);
}
LargeNumberCustom result = new LargeNumberCustom();
int carry = 0;
int maxDigits = Math.Min(x._digits.Count, MAX_DIGITS);
for (int i = 0; i < maxDigits; i++)
{
int prod = x._digits[x._digits.Count - i - 1] * y + carry;
result._digits.Insert(0, (byte)(prod % 10));
carry = prod / 10;
}
if (carry > 0)
{
result._digits.Insert(0, (byte)carry);
}
return(result);
}
public static LargeNumberCustom Power(LargeNumberCustom @base, int exp)
{
LargeNumberCustom result = 1;
for (int i = 0; i < exp; i++)
{
result = Multiply(result, @base);
}
return(result);
}
public static long Solve()
{
LargeNumberCustom result = 0;
for (int i = 1; i < 1001; i++)
{
result = result + LargeNumberCustom.Power(i, i);
}
Console.WriteLine(result);
return(0);
}
private static bool IsZero(LargeNumberCustom n)
{
return(n._digits.All(d => d == 0));
}
