1 files changed, 147 insertions, 0 deletions
diff --git a/DSACore/Auxiliary/SpellCorrect.cs b/DSACore/Auxiliary/SpellCorrect.cs
new file mode 100644
index 0000000..c9603f6
--- /dev/null
+++ b/DSACore/Auxiliary/SpellCorrect.cs
@@ -0,0 +1,147 @@
+namespace DSACore.Auxiliary
+{
+    using System;
+    using System.Diagnostics;
+    using System.Linq;
+
+    public class SpellCorrect : StringComparer
+    {
+        public const int ErrorThreshold = 94100;
+
+        public override int Compare(string x, string y)
+        {
+            return CompareEasy(x, y);
+        }
+
+        public static int CompareEasy(string x, string y)
+        {
+            if (string.IsNullOrEmpty(x))
+            {
+                throw new ArgumentException("message", nameof(x));
+            }
+
+            if (string.IsNullOrEmpty(y))
+            {
+                throw new ArgumentException("message", nameof(y));
+            }
+
+            if (x.Equals(y))
+            {
+                return 0;
+            }
+
+            x = x.ToLower();
+            y = y.ToLower();
+            if (x.Equals(y))
+            {
+                return 1;
+            }
+
+            var subs = y.Split(' ', '/');
+            int score = subs.Count();
+            foreach (string s in subs)
+            {
+                if (s.Equals(x))
+                {
+                    score--;
+                }
+            }
+
+            if (score < subs.Count())
+            {
+                return score + 1;
+            }
+
+            return 100000 - (int)(CompareExact(x, y) * 1000.0);
+            /*if (y.Contains(x))
+                return 6;*/
+        }
+
+        public override bool Equals(string x, string y)
+        {
+            Debug.Assert(x != null, nameof(x) + " != null");
+            return x.Equals(y);
+        }
+
+        public override int GetHashCode(string obj)
+        {
+            throw new NotImplementedException();
+        }
+
+        public static double CompareExact(string s, string q)
+        {
+
+            s = s.ToLower();
+            q = q.ToLower();
+
+            int i, j;
+            const double Match = 3.0;
+            const double Gap = -2.0;
+            const double Mismatch = -2.0;
+
+            double decay;
+
+            double[,] matrix = new double[s.Length + 1, q.Length + 1];
+            double max = 0.0;
+            matrix[0, 0] = 0.0;
+            
+            for (i = 1; i < s.Length; i++)
+            {
+               //  matrix[i, 0] = 0.0;
+                matrix[i, 0] = i * Gap;
+            }
+
+            for (i = 1; i < q.Length; i++)
+            {
+               matrix[0, i] = 0.0;
+            }
+
+
+            for (i = 1; i <= s.Length; i++)
+            {
+                for (j = 1; j <= q.Length; j++)
+                {
+                    decay = j / (double)(s.Length * 1000);
+                    double add = s[i - 1] == q[j - 1] ? (Match - decay) : Mismatch;
+                    double score = matrix[i - 1, j - 1] + add;
+
+                    if (score < (matrix[i - 1, j] + Gap))
+                    {
+                        score = matrix[i - 1, j] + Gap;
+                    }
+
+                    if (score < (matrix[i, j - 1] + Gap))
+                    {
+                        score = matrix[i, j - 1] + Gap;
+                    }
+
+                    if (i > 1 && j > 1)
+                    {
+                        if (s[i - 1] == q[j - 2] && s[i - 2] == q[j - 1])
+                        {
+                            add = (3 / 2.0) * Match - decay;
+                            if (score < matrix[i - 2, j - 2] + add)
+                            {
+                                score = matrix[i - 2, j - 2] + add;
+                            }
+                        }
+                    }
+                
+                  //  if (score < 0)
+                  //  {
+                  //      score = 0;
+                  // }
+
+                    if (max < score && i == s.Length)
+                    {
+                        max = score;
+                    }
+
+                    matrix[i, j] = score;
+                }
+            }
+
+            return max;
+        }
+    }
+}