new example code

diff --git a/kona/src/org/feistymeow/algorithms/SubstringFinder.java b/kona/src/org/feistymeow/algorithms/SubstringFinder.java
new file mode 100644 (file)
index 0000000..4e568b6
--- /dev/null
+++ b/kona/src/org/feistymeow/algorithms/SubstringFinder.java
@@ -0,0 +1,76 @@
+package org.feistymeow.algorithms;
+
+/**
+ * used to find strings in other strings.
+ *
+ * part of google interview prep.
+ */
+
+public class SubstringFinder
+{
+
+       /**
+        * returns the position of 'x' in 'y', or returns a negative number.
+        */
+       public int findXinY(String x, String y)
+       {
+               if ((x == null) || (y == null))
+                       return -1; // nulls are invalid to compare.
+               if (y.length() < x.length())
+                       return -1; // x cannot be found in shorter string.
+               for (int yIter = x.length() - 1; yIter < y.length(); yIter++) {
+                       boolean good = true;
+                       /*
+                        * xIter has to start at valid value in x, and that needs to be at end of x. board actually had uncorrected error here, where
+                        * xIter started at yIter, which is really wrong.
+                        */
+                       // simplified xIter which was inducing all sorts of OBOBs. even though i found the end in yIter,
+                       // i go forwards on xIter.
+                       for (int xIter = 0; xIter < x.length(); xIter++) {
+                               int yComparePosition = (yIter - x.length() + 1) + xIter;
+                               if (x.charAt(xIter) != y.charAt(yComparePosition)) {
+                                       // System.out.println("no match -- y[" + yIter + "]=" + y.charAt(yPosn) + " x[" + xIter + "]=" + x.charAt(xIter));
+                                       good = false;
+                                       break;
+                               }
+                       }
+                       if (good) {
+                               int toReturn = yIter - x.length() + 1;
+                               // System.out.println("found at position " +toReturn );
+                               return toReturn;
+                       }
+               }
+
+               return -1;
+       }
+
+       public static void main(String[] argv)
+       {
+               SubstringFinder sf = new SubstringFinder();
+
+               String x1 = "petunia";
+               String y1 = "sometimes my flowers are roses and sometimes they are petunias and sometimes they are turnips.";
+               if (sf.findXinY(x1, y1) != 54) {
+                       System.out.println("FAILURE: did not find at right index for test 1");
+               } else {
+                       System.out.println("OKAY: found substring at right index for test 1");
+               }
+
+               String x2 = "qn";
+               String y2 = "xaqno";
+               if (sf.findXinY(x2, y2) != 2) {
+                       System.out.println("FAILURE: did not find at right index for test 2");
+               } else {
+                       System.out.println("OKAY: found substring at right index for test 2");
+               }
+
+               String x3 = "qn";
+               String y3 = "xaqon";
+               if (sf.findXinY(x3, y3) >= 0) {
+                       System.out.println("FAILURE: found non-existent string for test 3");
+               } else {
+                       System.out.println("OKAY: did not find substring for test 3");
+               }
+
+       }
+}

diff --git a/nucleus/library/algorithms/sorts.h b/nucleus/library/algorithms/sorts.h
index 592f9903add6815118a4837c4669db0a685ebb29..c6e21abedc66ec69992016668e7e1ec51685db14 100644 (file)
--- a/nucleus/library/algorithms/sorts.h
+++ b/nucleus/library/algorithms/sorts.h
@@ -266,9 +266,9 @@ namespace algorithms {
                }
 
        private:
-               bool _reverse = false;  // is the sorting in reverse?
-               int _total = 0;
-               int *_heapspace = NULL_POINTER;
+               bool _reverse;  // is the sorting in reverse?
+               int _total;  // how many total elements are there?
+               int *_heapspace;  // track a pointer to the array.
        };
 
        /*!