8811. Product of two integers

Find the product of two integers.

Input. Two integers a and b (a, b ≤ 10⁹).

Output. Print the product of two integers.

Sample input	Sample output
3 7	21

SOLUTION

simple problem

Algorithm analysis

Since a, b ≤ 10⁹, then a * b ≤ 10¹⁸. Therefore, a 64-bit long long type should be used.

Algorithm realization

Read the values of the variables a and b.

scanf("%lld %lld", &a, &b);

Compute and print the product a * b.

p = a * b;

printf("%lld\n", p);

Algorithm realization – memory allocation with malloc

#include <stdio.h>

#include <malloc.h>

long long *a, *b, *res;

int main()

{

a = (long long *)malloc(8);

b = (long long *)malloc(8);

scanf("%lld %lld", a, b);

res = (long long *)malloc(8);

*res = *a * *b;

printf("%lld\n", *res);

free(a); free(b); free(res);

return 0;

}

Java realization

import java.util.*;

public class Main

{

public static void main(String[] args)

{

Scanner con = new Scanner(System.in);

long a = con.nextLong();

long b = con.nextLong();

long res = a * b;

System.out.println(res);

con.close();

}

}

Java realization – class MultInteger

import java.util.*;

class MultInteger

{

private long a;

MultInteger(long a)

{

this.a = a;

}

MultInteger Mult(MultInteger b)

{

return new MultInteger(a * b.a);

}

public String toString()

{

return String.valueOf(a);

}

}

public class Main

{

public static void main(String[] args)

{

Scanner con = new Scanner(System.in);

MultInteger a = new MultInteger(con.nextLong());

MultInteger b = new MultInteger(con.nextLong());

MultInteger res = a.Mult(b);

System.out.println(res);

con.close();

}

}

Python realization

Read the values of the variables a and b.

a, b = map(int,input().split())

Compute and print the product a * b.

res = a * b

print(res)