commit de8c5f3deb2318fde663763635db8f10943c8d50
Author: Nilstrieb <nils.heydecker@gmx.ch>
Date:   Mon May 17 15:41:10 2021 +0200

    knacken

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..59ae039
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+.idea
+*.iml
+/out
\ No newline at end of file
diff --git a/src/Caesar.java b/src/Caesar.java
new file mode 100644
index 0000000..2c9d2ca
--- /dev/null
+++ b/src/Caesar.java
@@ -0,0 +1,127 @@
+import java.util.*;
+import java.util.stream.Collectors;
+
+public class Caesar {
+    public static void main(String[] args) {
+        // System.out.println(normal("dies ist die erste uebung zum verschluesseln von mitteilungen", 9));
+
+        // System.out.println(withAlphabet("die verschluesselung mit dem kunterbunten geheimalphabet",
+        //          "LPAIQJBCTRWZYDSKEGFXHUONVM"));
+
+        // System.out.println(keyword("die matura wird nach sechs jahren gymnasium abgelegt", "kantonsschule"));
+
+        System.out.println(knacken("""
+                EHSSC NMVVPS FU YWP VM UVHSV EFU OFOVE CPHS HV EMTZHSVU
+                UREMMJ MO ZFVRERSHOV HLY ZFDHSYSC. EMZPXPS, ZEHV EHSSC FU
+                HAMWV VM YFURMXPS FL EFU LPZ CPHS HV EMTZHSVU ZFJJ VWSL EFU
+                ZMSJY WNUFYP YMZL…"""));
+        /*knacken2("""
+                XDY IKJKAHMCALYQDPECY SYOPECHRYPPYHRJB DPQ DI WYDQAHQYO XYP
+                EKIMRQYOP JDECQ IYCO AGQRYHH. PDY DPQ SDYH WR YDJZAEC WR
+                GJAEGYJ RJX PKIDQ ZRYO XYJ PDECYOYJ XAQYJARPQARPEC JDECQ
+                BYYDBJYQ""");*/
+    }
+
+    static String normal(String s, int shift) {
+        return s.toLowerCase().chars()
+                .map(c -> {
+                    if (isAlpha(c)) {
+                        int n = c + shift;
+                        if (n > Z) {
+                            n = (96 + (n - Z));
+                        }
+                        return n;
+                    }
+                    return c;
+                })
+                .mapToObj(i -> String.valueOf((char) i))
+                .collect(Collectors.joining());
+    }
+
+    static String withAlphabet(String s, String alphabet) {
+        final String a = alphabet.toLowerCase();
+        return s.toLowerCase().chars()
+                .map(c -> {
+                    if (isAlpha(c)) {
+                        int index = c - A;
+                        return a.charAt(index);
+                    }
+                    return c;
+                })
+                .mapToObj(i -> String.valueOf((char) i))
+                .collect(Collectors.joining());
+    }
+
+    private static final char Z = 122;
+    private static final char A = 97;
+
+    static String keyword(String s, String keyword) {
+        StringBuilder a = new StringBuilder();
+        for (char c : keyword.toCharArray()) {
+            if (!a.toString().contains(String.valueOf(c))) {
+                a.append(c);
+            }
+        }
+        int last = keyword.charAt(keyword.length() - 1);
+        for (int i = last + 1; i <= Z; i++) {
+            if (!a.toString().contains(String.valueOf((char) i))) {
+                a.append((char) i);
+            }
+        }
+        for (int i = A; i < last; i++) {
+            if (!a.toString().contains(String.valueOf((char) i))) {
+                a.append((char) i);
+            }
+        }
+
+        return withAlphabet(s, a.toString());
+    }
+
+    private static final String BUCHSTABEN = "enirsatdhulgocmbfwkzpvjyxq";
+    private static final String LETTERS = "etaoinsrhldcumfpgwybvkxjqz";
+
+    static String knacken(String s) {
+        HashMap<Character, Integer> chars = new HashMap<>();
+
+        s.toLowerCase().chars()
+                .filter(Caesar::isAlpha)
+                .forEach(c -> chars.merge((char) c, 1, Integer::sum));
+
+        // list an allen chars sortiert nach reihenfolge
+        List<Character> list = chars.entrySet().stream()
+                .sorted((e1, e2) -> Integer.compare(e2.getValue(), e1.getValue()))
+                .map(Map.Entry::getKey)
+                .toList();
+
+        for (char character : s.toCharArray()) {
+            if (list.contains((character))) {
+                System.err.println("wtf " + character);
+            }
+        }
+
+        List<Character> expected = new ArrayList<>();
+        LETTERS.chars().forEach(c -> expected.add((char) c));
+
+
+        return s.toLowerCase().chars()
+                .map(c -> {
+                    if (!isAlpha(c)) {
+                        return c;
+                    }
+                    return expected.get(list.indexOf((char) c));
+                })
+                .mapToObj(i -> String.valueOf((char) i))
+                .collect(Collectors.joining());
+    }
+
+    static void knacken2(String s) {
+        for (int i = 0; i < 26; i++) {
+            System.out.println(normal(s, i));
+        }
+    }
+
+
+    static boolean isAlpha(int c) {
+        return c <= 122 && c >= 97;
+    }
+}