uebung03

uebung03/src/polynomial/Polynomial.java

@@ -1,5 +1,187 @@
 package polynomial;
 
+import java.util.Arrays;
+
 public class Polynomial {
+    private final int[] werte;
+    private final int degree;
+
+    public Polynomial(int[] w) {
+        werte = w.clone();
+        int deg = 0;
+        for(int i = 0; i<w.length; i++){
+            if (werte[i] != 0){
+                deg = i;
+            }
+        }
+        degree = deg;
+        
+        //gleichwertige Variante
+        /*for (int i = w.length; i >= 0; i--) {
+            if (w[i] != 0) {
+                degree = i;
+            }
+        }*/
+    }
+
+    public Polynomial() {
+        this(new int[]{0,1});
+    }
+
+    //Option 1 Kopie des Arrays
+    public int[] getCoeef() {
+        return werte.clone();
+    }
+
+    //Option 2 Koeef an der Stelle i
+    public int getCoeefAt(int i) {
+        return i > degree ? 0 : werte[i];
+    }
+
+    public static Polynomial constant(int v) {
+        return new Polynomial(new int[]{v});
+    }
+
+    @Override
+    public String toString() {
+        if (isNull()){return "0";}
+        String result = "";
+
+        for (int i = degree; i >= 0; i--) {
+
+            if (werte[i] == 0) {continue;}
+
+            if (!result.isEmpty()) {
+                if (werte[i] > 0) {result += " + ";}
+                if (werte[i] < 0) {result += " - ";}
+            }
+
+            if (result.isEmpty() && werte[i] <0){result += "-";} // Minus am Anfang
+
+            int absCoeff = Math.abs(werte[i]);
+
+            if (absCoeff != 1 && i == 0) {result += absCoeff;}
+            if (absCoeff == 1 && i == 0) {result += "1";}
+            if (absCoeff != 1 && i != 0) {result += absCoeff +"*";}
+
+            if (i > 0) {
+                result += "x";
+                if (i > 1) {result += "^" + i;}
+            }
+
+        }
+        return result;
+    }
+
+    public Boolean isNull(){
+        for(int i = werte.length-1; i >= 0; i--){
+            if (werte[i] != 0) {
+                return false;
+            }
+        }
+        return true;
+
+    }
+
+    public String toString1() {
+        StringBuilder result = new StringBuilder();
+
+        for (int i = degree; i >= 0; i--) {
+
+            if (werte[i] == 0) {continue;}
+
+            if (!result.isEmpty()) {
+                if (werte[i] > 0) {result.append(" + ");}
+                if (werte[i] < 0) {result.append(" - ");}
+            }
+
+            if (result.isEmpty() && werte[i] <0){result.append("-");} // Minus am Anfang
+
+            int absCoeff = Math.abs(werte[i]);
+
+            if (absCoeff != 1 && i == 0) {result.append(absCoeff);}
+            if (absCoeff == 1 && i == 0) {result.append(1);}
+            if (absCoeff != 1 && i != 0) {
+                result.append(absCoeff);
+                result.append("*");}
+
+            if (i > 0) {
+                result.append("x");
+                if (i > 1) {result.append("^");
+                result.append(i);
+            }
+            }
+
+        }
+
+        return result.toString();
+    }
+
+    public Polynomial add(Polynomial p2){
+        int[] p1 = getCoeef();
+        int[] p2Coeff = p2.getCoeef();
+        int[] p3 = new int[Math.max(p1.length,p2Coeff.length)];
+        for(int x = p3.length-1; x >= 0; x --){
+            int coeff1 = (x < p1.length) ? p1[x] : 0;
+            int coeff2 = (x < p2Coeff.length) ? p2Coeff[x] : 0;
+            p3[x] = coeff1 + coeff2;
+        }
+        Polynomial result = new Polynomial(p3);
+        return result;
+    }
+
+    public Polynomial sub(Polynomial that) {
+        int[] res = Arrays.copyOf(werte, Math.max(this.degree, that.degree) + 1);
+        for (int i = 0; i <= that.degree; i++)
+            res[i] -= that.werte[i];
+        return new Polynomial(res);
+    }
+
+    public Polynomial mult(Polynomial that) {
+        int[] res = new int[this.degree + that.degree + 1];
+        Arrays.fill(res, 0);
+        for (int i = 0; i <= this.degree; i++)
+            for (int j = 0; j <= that.degree; j++)
+                res[i + j] += this.werte[i] * that.werte[j];
+        return new Polynomial(res);
+    }
+
+    public Polynomial exp(int e) {
+        if (e < 0)
+            throw new IllegalArgumentException("Exponent must not be negative");
+        else if (e == 0)
+            return constant(1);
+        else if (e == 1)
+            return this;
+        else if (e % 2 == 0)
+            return this.mult(this).exp(e / 2);
+        else
+            return this.mult(this.exp(e - 1));
+    }
+
+    public Polynomial add(int v) {
+        int[] res = Arrays.copyOf(werte, werte.length);
+        res[0] += v;
+        return new Polynomial(res);
+    }
+
+    public Polynomial sub(int v) {
+        return this.add(-v);
+    }
+
+    public Polynomial mult(int v) {
+        int[] res = Arrays.copyOf(werte, werte.length);
+        for (int j = 0; j < res.length; j++)
+            res[j] *= v;
+        return new Polynomial(res);
+    }
+
+    public int apply(int v) {
+        int res = werte[werte.length - 1];
+        for (int i = werte.length - 2; i >= 0; i--)
+            res = res + v * werte[i];
+        return res;
+    }
+
 
 }