import java.util.*; import java.util.zip.*; import java.util.List; import java.util.regex.*; import java.util.concurrent.*; import java.util.concurrent.atomic.*; import javax.swing.*; import javax.swing.event.*; import javax.swing.text.*; import javax.swing.table.*; import java.io.*; import java.net.*; import java.lang.reflect.*; import java.lang.ref.*; import java.lang.management.*; import java.security.*; import java.security.spec.*; import java.awt.*; import java.awt.event.*; import java.awt.image.*; import javax.imageio.*; import java.math.*; public class main { public static void main(String[] args) throws Exception { String s = "Hello world world world"; print("Original:\n " + s); String transformed = bwt(s, '|'); print("BWT Transformed:\n " + transformed); String x = inverseBWT(transformed, '|'); print("Transformed back:\n " + x); print(eq(s, x) ? "Yo!" : "No..."); print(); // Transform it again String doublyTransformed = bwt(transformed, '^'); print("Doubly Transformed (not very useful):\n " + doublyTransformed); } static String bwt(String input, char endMarker) { input += endMarker; int n = l(input); String[] tbl = new String[n]; for (int i = 0; i < n; i++) tbl[i] = rotateString(input, i); sort(tbl); StringBuilder buf = new StringBuilder(); for (int i = 0; i < n; i++) buf.append(last(tbl[i])); return str(buf); } static String rotateString(String s, int n) { if (n == 0) return s; return substring(s, l(s)-n) + substring(s, 0, l(s)-n); } static String inverseBWT(String s, char endMarker) { int n = l(s); String[] tbl = new String[n]; for (int i = 0; i < n; i++) tbl[i] = ""; for (int i = 0; i < n; i++) { // insert for (int j = 0; j < n; j++) tbl[j] = s.charAt(j) + tbl[j]; // sort sort(tbl); } for (int i = 0; i < n; i++) if (last(tbl[i]) == endMarker) return dropLast(tbl[i]); throw fail("NEVER FAIL in a perfect world!"); } static String str(Object o) { return String.valueOf(o); } static String[] dropLast(String[] a, int n) { n = Math.min(n, a.length); String[] b = new String[a.length-n]; System.arraycopy(a, 0, b, 0, b.length); return b; } static List dropLast(List l) { return subList(l, 0, l(l)-1); } static String dropLast(String s) { return substring(s, 0, l(s)-1); } static RuntimeException fail() { throw new RuntimeException("fail"); } static RuntimeException fail(Object msg) { throw new RuntimeException(String.valueOf(msg)); } static RuntimeException fail(String msg) { throw new RuntimeException(unnull(msg)); } // disabled for now to shorten some programs /*static RuntimeException fail(S msg, O... args) { throw new RuntimeException(format(msg, args)); }*/ static volatile StringBuffer local_log = new StringBuffer(); // not redirected static volatile StringBuffer print_log = local_log; // might be redirected, e.g. to main bot // in bytes - will cut to half that static volatile int print_log_max = 1024*1024; static volatile int local_log_max = 100*1024; //static int print_maxLineLength = 0; // 0 = unset static boolean print_silent; // total mute if set static void print() { print(""); } // slightly overblown signature to return original object... static A print(A o) { if (print_silent) return o; String s = String.valueOf(o) + "\n"; // TODO if (print_maxLineLength != 0) StringBuffer loc = local_log; StringBuffer buf = print_log; int loc_max = print_log_max; if (buf != loc && buf != null) { print_append(buf, s, print_log_max); loc_max = local_log_max; } if (loc != null) print_append(loc, s, loc_max); System.out.print(s); return o; } static void print(long l) { print(String.valueOf(l)); } static void print(char c) { print(String.valueOf(c)); } static void print_append(StringBuffer buf, String s, int max) { synchronized(buf) { buf.append(s); max /= 2; if (buf.length() > max) try { int newLength = max/2; int ofs = buf.length()-newLength; String newString = buf.substring(ofs); buf.setLength(0); buf.append("[...] ").append(newString); } catch (Exception e) { buf.setLength(0); } } } static A last(List l) { return l.isEmpty() ? null : l.get(l.size()-1); } static char last(String s) { return empty(s) ? '#' : s.charAt(l(s)-1); } static void sort(T[] a, Comparator c) { Arrays.sort(a, c); } static void sort(T[] a) { Arrays.sort(a); } static void sort(List a, Comparator c) { Collections.sort(a, c); } static void sort(List a) { Collections.sort(a); } static boolean eq(Object a, Object b) { if (a == null) return b == null; if (a.equals(b)) return true; if (a instanceof BigInteger) { if (b instanceof Integer) return a.equals(BigInteger.valueOf((Integer) b)); if (b instanceof Long) return a.equals(BigInteger.valueOf((Long) b)); } return false; } static int l(Object[] a) { return a == null ? 0 : a.length; } static int l(byte[] a) { return a == null ? 0 : a.length; } static int l(int[] a) { return a == null ? 0 : a.length; } static int l(float[] a) { return a == null ? 0 : a.length; } static int l(char[] a) { return a == null ? 0 : a.length; } static int l(Collection c) { return c == null ? 0 : c.size(); } static int l(Map m) { return m == null ? 0 : m.size(); } static int l(CharSequence s) { return s == null ? 0 : s.length(); } static int l(Object o) { return l((List) o); // incomplete } static String substring(String s, int x) { return safeSubstring(s, x); } static String substring(String s, int x, int y) { return safeSubstring(s, x, y); } static List subList(List l, int startIndex) { return subList(l, startIndex, l(l)); } static List subList(List l, int startIndex, int endIndex) { startIndex = max(0, min(l(l), startIndex)); endIndex = max(0, min(l(l), endIndex)); if (startIndex > endIndex) return litlist(); return l.subList(startIndex, endIndex); } static String unnull(String s) { return s == null ? "" : s; } static List unnull(List l) { return l == null ? emptyList() : l; } static Iterable unnull(Iterable i) { return i == null ? emptyList() : i; } static Object[] unnull(Object[] a) { return a == null ? new Object[0] : a; } static boolean empty(Collection c) { return isEmpty(c); } static boolean empty(String s) { return isEmpty(s); } static boolean empty(Map map) { return map == null || map.isEmpty(); } static boolean empty(Object[] o) { return o == null || o.length == 0; } static boolean empty(Object o) { if (o instanceof Collection) return empty((Collection) o); if (o instanceof String) return empty((String) o); if (o instanceof Map) return empty((Map) o); if (o instanceof Object[]) return empty((Object[]) o); throw fail("unknown type for 'empty': " + getType(o)); } // hopefully covers all cases :) static String safeSubstring(String s, int x, int y) { if (s == null) return null; if (x < 0) x = 0; if (x > s.length()) return ""; if (y < x) y = x; if (y > s.length()) y = s.length(); return s.substring(x, y); } static String safeSubstring(String s, int x) { return safeSubstring(s, x, l(s)); } static int max(int a, int b) { return Math.max(a, b); } static long max(int a, long b) { return Math.max((long) a, b); } static long max(long a, long b) { return Math.max(a, b); } static double max(int a, double b) { return Math.max((double) a, b); } static float max(float a, float b) { return Math.max(a, b); } static int max(Collection c) { int x = Integer.MIN_VALUE; for (int i : c) x = max(x, i); return x; } static double max(double[] c) { if (c.length == 0) return Double.MIN_VALUE; double x = c[0]; for (int i = 1; i < c.length; i++) x = Math.max(x, c[i]); return x; } static byte max(byte[] c) { byte x = -128; for (byte d : c) if (d > x) x = d; return x; } static boolean isEmpty(Collection c) { return c == null || c.isEmpty(); } static boolean isEmpty(CharSequence s) { return s == null || s.length() == 0; } static boolean isEmpty(Object[] a) { return a == null || a.length == 0; } static boolean isEmpty(Map map) { return map == null || map.isEmpty(); } static List emptyList() { return new ArrayList(); //ret Collections.emptyList(); } static int min(int a, int b) { return Math.min(a, b); } static double min(double a, double b) { return Math.min(a, b); } static double min(double[] c) { double x = Double.MAX_VALUE; for (double d : c) x = Math.min(x, d); return x; } static byte min(byte[] c) { byte x = 127; for (byte d : c) if (d < x) x = d; return x; } static String getType(Object o) { return getClassName(o); } static ArrayList litlist(A... a) { return new ArrayList(Arrays.asList(a)); } static String getClassName(Object o) { return o == null ? "null" : o.getClass().getName(); } }