fast io c++ geeksforgeeks
void fastscan(int &number)
{
//variable to indicate sign of input number
bool negative = false;
register int c;
number = 0;
// extract current character from buffer
c = getchar();
if (c=='-')
{
// number is negative
negative = true;
// extract the next character from the buffer
c = getchar();
}
// Keep on extracting characters if they are integers
// i.e ASCII Value lies from '0'(48) to '9' (57)
for (; (c>47 && c<58); c=getchar())
number = number *10 + c - 48;
// if scanned input has a negative sign, negate the
// value of the input number
if (negative)
number *= -1;
}
// Function Call
int main()
{
int number;
fastscan(number);
cout << number << "\n";
return 0;
}