全文关键字检索-KMP改进算法

正则可以实现关键字查找，但效率很低。就把KMP稍微修改，实现一个效率还比较好的KMP关键字查找算法。c#实现的。话不多说，贴代码。

//获取nextpublic static int[] GetKmpNext(string pattern){ int[] next = new int[pattern.Length]; next[0] = -1; if (pattern.Length < 2) return next; next[1] = 0; int i = 2, j = 0; while (i < pattern.Length) { if (pattern[i - 1] == pattern[j]) { next[i++] = ++j; } else { j = next[j]; if (j == -1) { next[i++] = ++j; } } } return next;}/// <summary>/// 查询关键字方法/// </summary>/// <param name="source">原字符串</param>/// <param name="keywords">关键字列表用|分开</param>/// <returns>如果存在关键字返回true，反之返回false。</returns>public static bool SearchKeywords(string source, string[] keywords){ int wordCount = keywords.Length; int[][] nexts = new int[wordCount][]; int i = 0; for (i = 0; i < wordCount; i++) { nexts[i] = GetKmpNext(keywords[i]); } i = 0; int[] j = new int[nexts.Length]; while (i < source.Length) { for (int k = 0; k < wordCount; k++) { if (source[i] == keywords[k][j[k]]) { j[k]++; } else { j[k] = nexts[k][j[k]]; if (j[k] == -1) { j[k]++; } } if (j[k] >= keywords[k].Length) { return true; } } i++; } return false;}//测试方法public static void Test(){ string[] keywords = "aa|bb|cc|dd|dddd|销售|报价|ee".Split("|".ToCharArray(), StringSplitOptions.RemoveEmptyEntries); string source = "测试这个adfedajk;ifn/"bb/"fdarew"; Console.WriteLine(SearchKeywords(source,keywords));}