88 lines
2.7 KiB
Java
88 lines
2.7 KiB
Java
package com.jwetherell.algorithms.mathematics;
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public class Division {
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public static final long division(int a, int b) {
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long result = ((long) a) / ((long) b);
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return result;
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}
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public static final long divisionUsingLoop(int a, int b) {
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int absA = Math.abs(a);
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int absB = Math.abs(b);
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long temp = absA;
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long result = 0;
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while (temp >= 0) {
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temp -= absB;
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if (temp >= 0)
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result++;
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}
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return (a > 0 && b > 0 || a < 0 && b < 0) ? result : -result;
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}
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public static final long divisionUsingRecursion(int a, int b) {
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int absA = Math.abs(a);
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int absB = Math.abs(b);
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long result = 1;
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int diff = absA - absB;
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if (diff > 0 && diff <= 1) {
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return result;
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} else if (diff < 0) {
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return 0;
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}
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result += divisionUsingRecursion(diff, absB);
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return (a > 0 && b > 0 || a < 0 && b < 0) ? result : -result;
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}
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public static final long divisionUsingMultiplication(int a, int b) {
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int absA = Math.abs(a);
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int absB = Math.abs(b);
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int temp = absB;
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int counter = 0;
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while (temp <= absA) {
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temp = temp << 1;
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counter++;
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}
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absA -= absB << (counter - 1);
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long result = (long) Math.pow(2, counter - 1);
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if (absB <= absA)
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result += divisionUsingMultiplication(absA, absB);
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return (a > 0 && b > 0 || a < 0 && b < 0) ? result : -result;
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}
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public static final long divisionUsingShift(int a, int b) {
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int absA = Math.abs(a);
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int absB = Math.abs(b);
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int tempA, tempB, counter;
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long result = 0L;
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while (absA >= absB) {
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tempA = absA >> 1; // Right shift "a"
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tempB = absB;
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counter = 1;
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while (tempA >= tempB) { // Double "tempB" until it's larger than
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// "tempA"
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tempB <<= 1;
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counter <<= 1; // Double the counter
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}
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absA -= tempB; // Subtract "tempB" from "a"
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result += counter; // Add counter (2^number of left shifts)
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}
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return (a > 0 && b > 0 || a < 0 && b < 0) ? result : -result;
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}
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public static final long divisionUsingLogs(int a, int b) {
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long absA = Math.abs(a);
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long absB = Math.abs(b);
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double logBase10A = Math.log10(absA);
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double logBase10B = Math.log10(absB);
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double powOf10 = Math.pow(10, (logBase10A - logBase10B));
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long result = (long) Math.floor(powOf10);
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return (a > 0 && b > 0 || a < 0 && b < 0) ? result : -result;
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}
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}
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