added Utils class, trying edit distance stuff for offset matching

pdex/src/processing/mode/experimental/Utils.java

@@ -0,0 +1,145 @@
+/*
+ * Copyright (C) 2012-14 Manindra Moharana <me@mkmoharana.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free Software
+ * Foundation; either version 2 of the License, or (at your option) any later
+ * version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+package processing.mode.experimental;
+
+/**
+ * A class containing multiple utility methods
+ * 
+ * @author Manindra Moharana <me@mkmoharana.com>
+ *
+ */
+
+public class Utils {
+  
+  public static int minDistance(String word1, String word2) {
+    int len1 = word1.length();
+    int len2 = word2.length();
+
+    // len1+1, len2+1, because finally return dp[len1][len2]
+    int[][] dp = new int[len1 + 1][len2 + 1];
+
+    for (int i = 0; i <= len1; i++) {
+      dp[i][0] = i;
+    }
+
+    for (int j = 0; j <= len2; j++) {
+      dp[0][j] = j;
+    }
+
+    //iterate though, and check last char
+    for (int i = 0; i < len1; i++) {
+      char c1 = word1.charAt(i);
+      for (int j = 0; j < len2; j++) {
+        char c2 = word2.charAt(j);
+        //System.out.print(c1 + "<->" + c2);
+        //if last two chars equal
+        if (c1 == c2) {
+          //update dp value for +1 length
+          dp[i + 1][j + 1] = dp[i][j];
+          System.out.println();
+        } else {
+          int replace = dp[i][j] + 1;
+          int insert = dp[i][j + 1] + 1;
+          int delete = dp[i + 1][j] + 1;
+//          if (replace < delete) {
+//            System.out.println(" --- D");
+//          } else
+//            System.out.println(" --- R");
+          int min = replace > insert ? insert : replace;
+          min = delete > min ? min : delete;
+          dp[i + 1][j + 1] = min;
+        }
+      }
+    }
+//    for (int i = 0; i < dp.length; i++) {
+//      for (int j = 0; j < dp[0].length; j++) {
+//        System.out.print(dp[i][j] + " ");
+//      }
+//      System.out.println();
+//    }
+
+    System.out.println("Edit distance1: " + dp[len1][len2]);
+    minDistInGrid(dp, 0, 0, len1, len2, word1.toCharArray(),
+                  word2.toCharArray());
+    return dp[len1][len2];
+  }
+
+  public static int distance(String a, String b) {
+//    a = a.toLowerCase();
+//    b = b.toLowerCase();
+
+    // i == 0
+    int[] costs = new int[b.length() + 1];
+    for (int j = 0; j < costs.length; j++)
+      costs[j] = j;
+    for (int i = 1; i <= a.length(); i++) {
+      // j == 0; nw = lev(i - 1, j)
+      costs[0] = i;
+      int nw = i - 1;
+      for (int j = 1; j <= b.length(); j++) {
+        int cj = Math.min(1 + Math.min(costs[j], costs[j - 1]),
+                          a.charAt(i - 1) == b.charAt(j - 1) ? nw : nw + 1);
+        nw = costs[j];
+        costs[j] = cj;
+      }
+    }
+    System.out.println("Edit distance2: " + costs[b.length()]);
+    return costs[b.length()];
+  }
+
+  public static void minDistInGrid(int g[][], int i, int j, int fi, int fj,
+                                   char s1[], char s2[]) {
+//    if(i < s1.length)System.out.print(s1[i] + " <->");
+//    if(j < s2.length)System.out.print(s2[j]);
+    if (i < s1.length && j < s2.length) {
+      System.out.print(s1[i] + " <-> " + s2[j]);
+      if (s1[i] != s2[j])
+        System.out.println("--");
+    }
+    System.out.println();
+    if (i == fi && j == fj) {
+      System.out.println("Reached end.");
+    } else {
+      int a = Integer.MAX_VALUE, b = a, c = a;
+      if (i < fi)
+        a = g[i + 1][j];
+      if (i < fi && j < fj)
+        b = g[i][j + 1];
+      if (i < fi && j < fj)
+        c = g[i + 1][j + 1];
+      int mini = Math.min(a, Math.min(b, c));
+      if (mini == a) {
+        //System.out.println(s1[i + 1] + " " + s2[j]);
+        minDistInGrid(g, i + 1, j, fi, fj, s1, s2);
+      } else if (mini == b) {
+        //System.out.println(s1[i] + " " + s2[j + 1]);
+        minDistInGrid(g, i, j + 1, fi, fj, s1, s2);
+      } else if (mini == c) {
+        //System.out.println(s1[i + 1] + " " + s2[j + 1]);
+        minDistInGrid(g, i + 1, j + 1, fi, fj, s1, s2);
+      }
+    }
+  }
+
+  public static void main(String[] args) {
+    minDistance("c = #qwerty;", "c = 0xffqwerty;");
+    //minDistance("c = #bb00aa;", "c = 0xffbb00aa;");
+//    distance("c = #bb00aa;", "c = 0xffbb00aa;");
+  }
+}