logo

Vermenigvuldiging van twee getallen met ploegoperator

Voor elke gegeven twee getallen n en m moet je n*m ​​vinden zonder een vermenigvuldigingsoperator te gebruiken. 
Voorbeelden:  

Input: n = 25  m = 13 Output: 325 Input: n = 50  m = 16 Output: 800

Methode 1
Dit probleem kunnen wij oplossen met de ploegoperator. Het idee is gebaseerd op het feit dat elk getal in binaire vorm kan worden weergegeven. En vermenigvuldiging met een getal is gelijk aan vermenigvuldiging met machten van 2. Machten van 2 kunnen worden verkregen met behulp van de linkershiftoperator.
Controleer voor elke ingestelde bit in de binaire representatie van m en voor elke ingestelde bit naar links, verschuif n teltijden waar tel als de waarde van de ingestelde bit van m wordt geplaatst en tel die waarde op om te antwoorden.
 

C++
// CPP program to find multiplication // of two number without use of // multiplication operator #include   using namespace std; // Function for multiplication int multiply(int n int m) {   int ans = 0 count = 0;  while (m)  {  // check for set bit and left   // shift n count times  if (m % 2 == 1)   ans += n << count;  // increment of place value (count)  count++;  m /= 2;  }  return ans; } // Driver code int main() {  int n = 20  m = 13;  cout << multiply(n m);  return 0; } 
Java
// Java program to find multiplication // of two number without use of // multiplication operator class GFG {    // Function for multiplication  static int multiply(int n int m)  {   int ans = 0 count = 0;  while (m > 0)  {  // check for set bit and left   // shift n count times  if (m % 2 == 1)   ans += n << count;    // increment of place   // value (count)  count++;  m /= 2;  }    return ans;  }    // Driver code  public static void main (String[] args)  {  int n = 20 m = 13;    System.out.print( multiply(n m) );  } } // This code is contributed by Anant Agarwal. 
Python3
# python 3 program to find multiplication # of two number without use of # multiplication operator # Function for multiplication def multiply(n m): ans = 0 count = 0 while (m): # check for set bit and left  # shift n count times if (m % 2 == 1): ans += n << count # increment of place value (count) count += 1 m = int(m/2) return ans # Driver code if __name__ == '__main__': n = 20 m = 13 print(multiply(n m)) # This code is contributed by # Ssanjit_Prasad 
C#
// C# program to find multiplication // of two number without use of // multiplication operator using System; class GFG {    // Function for multiplication  static int multiply(int n int m)  {   int ans = 0 count = 0;  while (m > 0)  {  // check for set bit and left   // shift n count times  if (m % 2 == 1)   ans += n << count;    // increment of place   // value (count)  count++;  m /= 2;  }    return ans;  }    // Driver Code  public static void Main ()  {  int n = 20 m = 13;    Console.WriteLine( multiply(n m) );  } } // This code is contributed by vt_m. 
PHP
 // PHP program to find multiplication // of two number without use of // multiplication operator // Function for multiplication function multiply( $n $m) { $ans = 0; $count = 0; while ($m) { // check for set bit and left  // shift n count times if ($m % 2 == 1) $ans += $n << $count; // increment of place value (count) $count++; $m /= 2; } return $ans; } // Driver code $n = 20 ; $m = 13; echo multiply($n $m); // This code is contributed by anuj_67. ?> 
JavaScript
<script> // JavaScript program to find multiplication  // of two number without use of  // multiplication operator  // Function for multiplication  function multiply(n m)  {   let ans = 0 count = 0;   while (m)   {   // check for set bit and left   // shift n count times   if (m % 2 == 1)   ans += n << count;   // increment of place value (count)   count++;   m = Math.floor(m / 2);   }   return ans;  }  // Driver code   let n = 20  m = 13;   document.write(multiply(n m));    // This code is contributed by Surbhi Tyagi. </script> 

Uitvoer
260


Tijdcomplexiteit: O(logboek n)



Hulpruimte: O(1)

Methode 2

We kunnen de shift-operator in lussen gebruiken.

C++
#include    using namespace std;   int multiply(int n int m){  bool isNegative = false;  if (n < 0 && m < 0) {  n = -n m = -m;  }  if (n < 0) {  n = -n isNegative = true;  }  if (m < 0) {  m = -m isNegative = true;  }   int result = 0;  while (m){  if (m & 1) {  result += n;  }  // multiply a by 2  n = n << 1;  // divide b by 2  m = m >> 1;  }  return (isNegative) ? -result : result; }   int main() {  int n = 20  m = 13;  cout << multiply(n m);  return 0; } 
Java
// Java program for the above approach import java.io.*; class GFG {    public static int multiply(int n int m){  boolean isNegative = false;  if (n < 0 && m < 0) {  n = -n;  m = -m;  }  if (n < 0) {  n = -n;  isNegative = true;  }  if (m < 0) {  m = -m;  isNegative = true;  }  int result = 0;  while (m>0){  if ((m & 1)!=0) {  result += n;  }  // multiply a by 2  n = n << 1;  // divide b by 2  m = m >> 1;  }  return (isNegative) ? -result : result; }  public static void main (String[] args) {  int n = 20  m = 13;  System.out.println(multiply(n m));  } } // This code is contributed by Pushpesh Raj. 
Python3
def multiply(n m): is_negative = False if n < 0 and m < 0: n m = -n -m if n < 0: n is_negative = -n True if m < 0: m is_negative = -m True result = 0 while m: if m & 1: result += n # multiply a by 2 n = n << 1 # divide b by 2 m = m >> 1 return -result if is_negative else result n = 20 m = 13 print(multiply(n m)) 
C#
// C# program for the above approach using System; class GFG {    public static int multiply(int n int m){  bool isNegative = false;  if (n < 0 && m < 0) {  n = -n;  m = -m;  }  if (n < 0) {  n = -n;  isNegative = true;  }  if (m < 0) {  m = -m;  isNegative = true;  }  int result = 0;  while (m>0){  if ((m & 1)!=0) {  result += n;  }  // multiply a by 2  n = n << 1;  // divide b by 2  m = m >> 1;  }  return (isNegative) ? -result : result; }  public static void Main () {  int n = 20  m = 13;  Console.WriteLine(multiply(n m));  } } // This code is contributed by Utkarsh 
JavaScript
function multiply(n m) {  let isNegative = false;  if (n < 0 && m < 0) {  n = -n m = -m;  }  if (n < 0) {  n = -n isNegative = true;  }  if (m < 0) {  m = -m isNegative = true;  }  let result = 0;  while (m) {  if (m & 1) {  result += n;  }  // multiply a by 2  n = n << 1;  // divide b by 2  m = m >> 1;  }  return (isNegative) ? -result : result; } console.log(multiply(20 13)); 

Uitvoer
260

Tijdcomplexiteit: O(log(m))

Hulpruimte: O(1)

  Related Article:      Russian Peasant (Multiply two numbers using bitwise operators)   
Quiz maken