//******************************************************************************************************//  LongestCommonSubstring.cs - Gbtc////  Copyright © 2013, Grid Protection Alliance.  All Rights Reserved.////  Licensed to the Grid Protection Alliance (GPA) under one or more contributor license agreements. See//  the NOTICE file distributed with this work for additional information regarding copyright ownership.//  The GPA licenses this file to you under the MIT License (MIT), the "License"; you may//  not use this file except in compliance with the License. You may obtain a copy of the License at:////      http://www.opensource.org/licenses/MIT////  Unless agreed to in writing, the subject software distributed under the License is distributed on an//  "AS-IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. Refer to the//  License for the specific language governing permissions and limitations.////  Code Modification History://  ----------------------------------------------------------------------------------------------------//  04/14/2013 - Kevin D. Jones//       Generated original version of source code.////****************************************************************************************************** using System;using System.Diagnostics.CodeAnalysis;using System.Text; // TODO: Please add comments to these classes#pragma warning disable 1591 namespace GSF.FuzzyStrings{    public static partial class ComparisonMetrics    {        [SuppressMessage("Microsoft.Performance", "CA1814:PreferJaggedArraysOverMultidimensional")]        public static string LongestCommonSubstring(this string source, string target)        {            if (String.IsNullOrEmpty(source) || String.IsNullOrEmpty(target))            {                return null;            }             int[,] L = new int[source.Length, target.Length];            int maximumLength = 0;            int lastSubsBegin = 0;            StringBuilder stringBuilder = new StringBuilder();             for (int i = 0; i < source.Length; i++)            {                for (int j = 0; j < target.Length; j++)                {                    if (source[i] != target[j])                    {                        L[i, j] = 0;                    }                    else                    {                        if ((i == 0) || (j == 0))                            L[i, j] = 1;                        else                            L[i, j] = 1 + L[i - 1, j - 1];                         if (L[i, j] > maximumLength)                        {                            maximumLength = L[i, j];                            int thisSubsBegin = i - L[i, j] + 1;                            if (lastSubsBegin == thisSubsBegin)                            {//if the current LCS is the same as the last time this block ran                                stringBuilder.Append(source[i]);                            }                            else //this block resets the string builder if a different LCS is found                            {                                lastSubsBegin = thisSubsBegin;                                stringBuilder.Length = 0; //clear it                                stringBuilder.Append(source.Substring(lastSubsBegin, (i + 1) - lastSubsBegin));                            }                        }                    }                }            }             return stringBuilder.ToString();        }     }}