Zadanie 02

02-Wielomiany/src/DivisionErrorException.java

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+public class DivisionErrorException extends Throwable {
+    public DivisionErrorException() {
+        System.out.println("Division error!");
+    }
+}

02-Wielomiany/src/Main.java

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+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class Main {
+
+    public static void main(String[] args) throws DivisionErrorException, MultiplierNotFoundException {
+        //ex input in run console : 2 "1 1 1 0 1" "0 1 1"
+        int n = Integer.parseInt(args[0]);
+        List<Integer> firstPolynomial = new ArrayList<>();
+        Arrays.asList(args[1].split("\\s* \\s*")).forEach(factor -> firstPolynomial.add(Integer.valueOf(factor)));
+        List<Integer> secondPolynomial = new ArrayList<>();
+        Arrays.asList(args[2].split("\\s* \\s*")).forEach(factor -> secondPolynomial.add(Integer.valueOf(factor)));
+        PolynomialTask polynomialTask = new PolynomialTask(n, firstPolynomial, secondPolynomial);
+        polynomialTask.printAllValuesToStandardOutput();
+    }
+}

02-Wielomiany/src/MultiplierNotFoundException.java

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+public class MultiplierNotFoundException extends Throwable {
+    public MultiplierNotFoundException() {
+        System.out.println("DivisionError");
+    }
+}

02-Wielomiany/src/PolynomialTask.java

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+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class PolynomialTask {
+    private int n;
+
+    private List<Integer> firstPolynomial;
+    private List<Integer> secondPolynomial;
+
+    public PolynomialTask(int n, List<Integer> firstPoly, List<Integer> secondPoly) {
+        this.n = n;
+        this.firstPolynomial = firstPoly;
+        this.secondPolynomial = secondPoly;
+    }
+
+    public Integer[] multiplyPolynomials(List<Integer> firstPolynomial, List<Integer> secondPolynomial) {
+        int[] multiplied = new int[firstPolynomial.size() + secondPolynomial.size() - 1];
+        int sizeOfFirstPoly = firstPolynomial.size();
+        int sizeOfSecondPoly = secondPolynomial.size();
+        for (int i = 0; i < sizeOfFirstPoly; i++) {
+            for (int j = 0; j < sizeOfSecondPoly; j++)
+                multiplied[i + j] = (multiplied[i + j] + (firstPolynomial.get(i) * secondPolynomial.get(j))) % n;
+        }
+        return Arrays.stream(multiplied).boxed().toArray(Integer[]::new);
+    }
+
+    public int[] moduloDividePolynomialsReturnQuotient(List<Integer> firstPoly, List<Integer> secondPoly) throws MultiplierNotFoundException, DivisionErrorException {
+        int[] quotient = new int[firstPoly.size() + secondPoly.size()];
+        int firstPolyDegree = firstPoly.size() - 1;
+        int secondPolyDegree = secondPoly.size() - 1;
+        List<Integer> polynomialAfterSubtract = firstPoly;
+
+
+        while (firstPolyDegree >= secondPolyDegree) {
+            polynomialAfterSubtract = calcQuotient(polynomialAfterSubtract, secondPoly, quotient);
+            firstPolyDegree = polynomialAfterSubtract.size() - 1;
+        }
+
+        int[] remainder = new int[polynomialAfterSubtract.size()];
+        for (int i = 0; i < polynomialAfterSubtract.size(); i++) {
+            remainder[i] = polynomialAfterSubtract.get(i);
+        }
+        return remainder;
+    }
+
+    private List<Integer> calcQuotient(List<Integer> firstPoly, List<Integer> secondPoly, int[] quotient) throws MultiplierNotFoundException, DivisionErrorException {
+        int firstPolyDegree = firstPoly.size() - 1;
+        int secondPolyDegree = secondPoly.size() - 1;
+        if (firstPolyDegree < secondPolyDegree) {
+            throw new DivisionErrorException();
+        }
+        int quotientCoefficient;
+        if ((((float) firstPoly.get(firstPolyDegree) / (float) secondPoly.get(secondPolyDegree))) == Math.round(firstPoly.get(firstPolyDegree) / secondPoly.get(secondPolyDegree))) {
+            quotientCoefficient = firstPoly.get(firstPolyDegree) / secondPoly.get(secondPolyDegree);
+        } else {
+            quotientCoefficient = invElem(firstPoly.get(firstPolyDegree), secondPoly.get(secondPolyDegree));
+        }
+        quotient[firstPolyDegree - secondPolyDegree] += quotientCoefficient;
+        List<Integer> newPoly = generatePolyFromIndexAndValue(firstPolyDegree - secondPolyDegree, quotientCoefficient);
+        Integer[] multipliedPolynomials = multiplyPolynomials(newPoly, secondPoly);
+        List<Integer> polynomialAfterFirstDivide = new ArrayList<>(Arrays.asList(multipliedPolynomials));
+
+        return removeUnnecessaryZeros(subtractTwoPolynomials(firstPoly, polynomialAfterFirstDivide));
+    }
+
+    private List<Integer> removeUnnecessaryZeros(List<Integer> polynomialAfterSubtract) {
+        int amountOfZeros = 0;
+        for (int i = polynomialAfterSubtract.size() - 1; i >= 0; i--) {
+            if (polynomialAfterSubtract.get(i) == 0) {
+                amountOfZeros++;
+            } else {
+                break;
+            }
+        }
+
+        polynomialAfterSubtract = polynomialAfterSubtract.subList(0, polynomialAfterSubtract.size() - amountOfZeros);
+        return polynomialAfterSubtract;
+    }
+
+    private List<Integer> subtractTwoPolynomials(List<Integer> firstPoly, List<Integer> secondPoly) {
+        List<Integer> subtractedPolynomial = new ArrayList<>(Collections.nCopies(firstPoly.size() + secondPoly.size(), 0));
+        for (int index = firstPoly.size(); index >= 0; index--) {
+            if (index < secondPoly.size()) {
+                subtractedPolynomial.set(index, firstPoly.get(index) - secondPoly.get(index));
+                parseNegativeElement(subtractedPolynomial, index);
+            }
+        }
+        return subtractedPolynomial;
+    }
+
+    private void parseNegativeElement(List<Integer> subtractedPolynomial, int index) {
+        while (subtractedPolynomial.get(index) < 0)
+            subtractedPolynomial.set(index, (subtractedPolynomial.get(index) * subtractedPolynomial.get(index)) % n);
+    }
+
+    private List<Integer> generatePolyFromIndexAndValue(int size, int quotientCoefficient) {
+        List<Integer> poly = new ArrayList<>(Collections.nCopies(size + 1, 0));
+        poly.set(size, quotientCoefficient);
+        return poly;
+    }
+
+    private int invElem(int a, int b) throws MultiplierNotFoundException {
+
+        for (int i = 0; i < n; i++) {
+            if (a == (b * i) % n) {
+                return i;
+            }
+        }
+
+        throw new MultiplierNotFoundException();
+    }
+
+    public void printAllValuesToStandardOutput() throws DivisionErrorException, MultiplierNotFoundException {
+        List<List<Integer>> values = new ArrayList<>();
+        values.add(Arrays.asList(multiplyPolynomials(firstPolynomial, secondPolynomial)));
+        values.add(Arrays.stream(moduloDividePolynomialsReturnQuotient(firstPolynomial, secondPolynomial)).boxed().collect(Collectors.toList()));
+        try {
+            values.add(gcd(firstPolynomial, secondPolynomial));
+        } catch (MultiplierNotFoundException e) {
+        }
+        System.out.println(values);
+    }
+
+    private List<Integer> gcd(List<Integer> polyOne, List<Integer> polyTwo) throws MultiplierNotFoundException, DivisionErrorException {
+        if (polyTwo.isEmpty()) return polyOne;
+        List<Integer> poly = Arrays.stream(moduloDividePolynomialsReturnQuotient(polyOne, polyTwo)).boxed().collect(Collectors.toList());
+        return gcd(polyTwo, poly);
+
+    }
+
+}