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Perform Integer Division Without Using Either the / or * Operators
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public class Answer28 { | |
private static long dividend = 1; | |
private static long divisor = 1; | |
public static long divideOne(long dividend, long divisor) { | |
long quotient = 0; | |
if(dividend <= 0 || divisor <= 0 || dividend < divisor) | |
return 0; | |
while (dividend >= divisor) { | |
dividend -= divisor; | |
quotient++; | |
} | |
System.out.println("(divideOne): Answer: " + quotient); | |
return quotient; | |
} | |
//http://www.dragonwins.com/domains/getteched/de248/binary_division.htm | |
public static long divideTwo(long dividend, long divisor) { | |
long quotient = 0; | |
if(dividend <= 0 || divisor <= 0 || dividend < divisor) | |
return 0; | |
// term * divisor should be close to dividend | |
long term = 1; | |
//System.out.println(dividend + " " + divisor + " " + term + " " + quotient); | |
while((term < Math.pow(2,64 - 1)) && (divisor < dividend)) | |
{ | |
divisor = divisor << 1; | |
term = term << 1; | |
//System.out.println(dividend + " " + divisor + " " + term + " " + quotient); | |
} | |
while(term >= 1) | |
{ | |
if(divisor <= dividend) | |
{ | |
//System.out.println(dividend + " " + divisor + " " + term + " " + quotient); | |
quotient += term; | |
dividend = dividend - divisor; | |
} | |
//System.out.println(dividend + " " + divisor + " " + term + " " + quotient); | |
divisor = divisor >> 1; | |
term = term >> 1; | |
} | |
System.out.println("(divideTwo): Answer: " + quotient); | |
return quotient; | |
} | |
} |
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