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-rw-r--r--Algorithms/Part-II/4-Boggle/BoggleSolverDicho.java305
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diff --git a/Algorithms/Part-II/4-Boggle/BoggleSolverDicho.java b/Algorithms/Part-II/4-Boggle/BoggleSolverDicho.java
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+++ b/Algorithms/Part-II/4-Boggle/BoggleSolverDicho.java
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+/* vim: set expandtab tabstop=4 shiftwidth=4 : */
+
+import java.util.Set;
+import java.util.HashSet;
+import java.util.Arrays;
+
+public class BoggleSolverDicho
+{
+
+ private class BoggleDictState
+ {
+ private String s;
+ private int idx, from, to;
+ private boolean isWord;
+
+ public BoggleDictState(int from, int to)
+ {
+ this.s = "";
+ this.idx = -1;
+ this.from = from;
+ this.to = to;
+ this.isWord = false;
+ }
+
+ public BoggleDictState(String s, int idx, int from, int to,
+ boolean isWord)
+ {
+ this.s = s;
+ this.idx = idx;
+ this.from = from;
+ this.to = to;
+ this.isWord = isWord;
+ }
+
+ public String s() { return s; }
+ public int idx() { return idx; }
+ public int from() { return from; }
+ public int to() { return to; }
+ public boolean isWord() { return isWord; }
+ public int n() { return (to - from + 1); }
+
+ public String toString(String[] words)
+ {
+ String ret = s + "(" + idx + ") " + isWord + " "
+ + " [" + from + ";" + to + "](" + n()+") ";
+
+ if (from > 0) ret += words[from - 1];
+ ret += " ["+words[from]+"..."+words[to]+"] ";
+ if (to < (words.length - 1)) ret += words[to + 1];
+
+ return ret;
+ }
+ }
+
+ private class BoggleDict
+ {
+ private String[] words;
+
+ public BoggleDict(String[] words)
+ {
+ this.words = Arrays.copyOf(words, words.length);
+ }
+
+ public int size()
+ {
+ return words.length;
+ }
+
+ public boolean exists(String word) {
+ if (word.isEmpty()) return false;
+
+ BoggleDictState st = new BoggleDictState(0, (size() - 1));
+ for (int i = 0; i < word.length(); i++) {
+ st = filter(word.charAt(i), st);
+ if (st == null) return false;
+ }
+
+ return st.isWord();
+ }
+
+ private BoggleDictState filter(char c, BoggleDictState st)
+ {
+ int idx = st.idx() + 1;
+ int from = st.from();
+ int to = st.to();
+ int n = st.n();
+
+ if (words[from].length() <= idx) {
+ if (n == 1) return null;
+ from++;
+ }
+
+ boolean fromOk = (words[from].charAt(idx) == c);
+ boolean toOk = (words[to].charAt(idx) == c);
+
+ if (!fromOk && (n == 1)) return null;
+
+ // if (n < 200) {
+ // // lower bound
+ // if (!fromOk) {
+ // for (int i = from; i <= to; i++) {
+ // if (words[i].charAt(idx) == c) {
+ // fromOk = true;
+ // from = i;
+ // break;
+ // }
+ // }
+ // if (!fromOk) return null;
+ // }
+ // // upper bound
+ // if (!toOk) {
+ // for (int i = to; i >= from; i--) {
+ // if (words[i].charAt(idx) == c) {
+ // toOk = true;
+ // to = i;
+ // break;
+ // }
+ // }
+ // if (!toOk) return null;
+ // }
+ // }
+ // lower bound
+ if (!fromOk) {
+ int tob = to;
+
+ int mid = (from + tob) / 2;
+ while (mid != from) {
+
+ int diff = words[mid].charAt(idx) - c;
+
+ if (diff > 0) {
+ to = mid;
+ tob = mid;
+ } else if (diff < 0)
+ from = mid;
+ else
+ tob = mid;
+
+ mid = (tob + from) / 2;
+ }
+ if (!(words[from].charAt(idx) == c)) {
+ if (words[tob].charAt(idx) == c) from = tob;
+ else return null;
+ }
+ }
+
+ // upper bound
+ if (!toOk) {
+ int fromb = from;
+ int mid = (fromb + to) / 2;
+ while (mid != fromb) {
+
+ int diff = words[mid].charAt(idx) - c;
+
+ if (diff <= 0)
+ fromb = mid;
+ else
+ to = mid;
+
+ mid = (fromb + to) / 2;
+ }
+ if (!(words[to].charAt(idx) == c)) {
+ if (words[fromb].charAt(idx) == c) to = fromb;
+ else return null;
+ }
+ }
+
+ boolean isWord = ((idx > 1) && ((words[from].length() - 1) == idx));
+
+ return new BoggleDictState((st.s() + c), idx, from, to, isWord);
+ }
+ }
+
+ private int cols, rows;
+ private BoggleDict dict;
+ private BoggleBoard board;
+ private boolean[] visited;
+ private Set<String> result;
+
+ // assume each word in the dictionary contains only [A-Z]
+ public BoggleSolverDicho(String[] dictionary)
+ {
+ dict = new BoggleDict(dictionary);
+ }
+
+ // Returns the set of all valid words in the given Boggle board
+ public Iterable<String> getAllValidWords(BoggleBoard b)
+ {
+ this.board = b;
+ this.cols = board.cols();
+ this.rows = board.rows();
+ this.result = new HashSet<String>();
+
+ BoggleDictState emptyState = new BoggleDictState(0, (dict.size() - 1));
+ for (int r = 0; r < this.rows; r++) {
+ for (int c = 0; c < this.cols; c++) {
+ this.visited = new boolean[this.rows * this.cols];
+ explore(r, c, emptyState);
+ }
+ }
+
+ return result;
+ }
+
+ //
+ private void explore(int r, int c, BoggleDictState current)
+ {
+ if ((r < 0) || (r >= rows) || (c < 0) || (c >= cols)) return;
+
+ int visitedIdx = (r * this.cols) + c;
+ if (visited[visitedIdx]) return;
+
+ char ch = board.getLetter(r, c);
+ BoggleDictState next = dict.filter(ch, current);
+ if (next == null) return;
+ if (ch == 'Q') {
+ next = dict.filter('U', next);
+ if (next == null) return;
+ }
+
+ if (next.isWord()) result.add(next.s());
+
+ visited[visitedIdx] = true;
+
+ explore((r - 1), (c - 1), next);
+ explore((r - 1), c, next);
+ explore((r - 1), (c + 1), next);
+ explore(r, (c - 1), next);
+ explore(r, (c + 1), next);
+ explore((r + 1), (c - 1), next);
+ explore((r + 1), c, next);
+ explore((r + 1), (c + 1), next);
+
+ visited[visitedIdx] = false;
+ }
+
+ // Returns the score if it is in the dictionary, zero otherwise.
+ // assume the word contains only [A-Z]
+ public int scoreOf(String word)
+ {
+ if (!dict.exists(word)) return 0;
+
+ int l = word.length();
+ if (l < 3) {
+ return 0;
+ } else if (l < 5) {
+ return 1;
+ } else if (l < 6) {
+ return 2;
+ } else if (l < 7) {
+ return 3;
+ } else if (l < 8) {
+ return 5;
+ } else {
+ return 11;
+ }
+ }
+
+ public static void main(String[] args)
+ {
+ if (args[0].equals("timing")) {
+ In in = new In("./data/dictionary-yawl.txt");
+ String[] dictionary = in.readAllStrings();
+
+ Stopwatch w = new Stopwatch();
+ BoggleSolver solver = new BoggleSolver(dictionary);
+ double dt = +w.elapsedTime();
+ System.out.println("construction : "+dt);
+
+ String s = "board-pneumonoultramicroscopicsilicovolcanoconiosis.txt";
+ BoggleBoard []boards = new BoggleBoard[5];
+ boards[0] = new BoggleBoard("./data/board-points4527.txt");
+ boards[1] = new BoggleBoard("./data/board-points13464.txt");
+ boards[2] = new BoggleBoard("./data/board-points4410.txt");
+ boards[3] = new BoggleBoard("./data/board-points1250.txt");
+ boards[4] = new BoggleBoard("./data/board-points1500.txt");
+ // boards[1] = new BoggleBoard("./data/board-rotavator.txt");
+ // boards[2] = new BoggleBoard("./data/board-16q.txt");
+ // boards[4] = new BoggleBoard("./data/" + s);
+
+
+ for (int t = 0; t < 5; t++) {
+ w = new Stopwatch();
+ for (int i = 0; i < 3000; i++) {
+ solver.getAllValidWords(boards[i % 5]);
+ }
+ dt = +w.elapsedTime();
+ System.out.println("search time : "+dt);
+ }
+ } else {
+ In in = new In(args[0]);
+ String[] dictionary = in.readAllStrings();
+ BoggleSolverDicho solver = new BoggleSolverDicho(dictionary);
+ BoggleBoard board = new BoggleBoard(args[1]);
+ int score = 0;
+ for (String word : solver.getAllValidWords(board))
+ {
+ StdOut.println(word);
+ score += solver.scoreOf(word);
+ }
+ StdOut.println("Score = " + score);
+ StdOut.println("Score = " + solver.scoreOf("REQUEST"));
+ }
+ }
+}
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