Virat And Factorial problem

#1

In the hint it is given that we can use string_multiplication or bit int but when i am using string multiplication it is giving time limit exceeded can you tell me the reason

#2

@amangoel987357 Use array for storing the digits of the multiplication. Use the basic childhood method we use for multiplication using carrys and remainders.

#3

@amangoel987357 You can take this for your help:
ll multiply( ll x , vector& v , ll dig) {
ll carry = 0;
for ( int i = 0; i < dig; i++) {
ll prod = v[i] * x + carry;
v[i] = prod % 10;
carry = prod / 10;
}
while (carry > 0) {

    v[dig] = carry % 10;
    carry /= 10;
    dig++;
}
return dig;

}
void fact ( ll n) {
vector v(500, 0);
v[0] = 1;
v[1] = 1;
ll dig = 1;
for ( int i = 2; i <= n; i++) {
dig = multiply(i, v, dig);
}
for ( int i = dig - 1; i >= 0; i–) {
cout << v[i] << “”;
}
}

#4

Hey buddy i am using childhood method only

#5

Did you get that? I have already sent you the approach.

#6

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