BF算法与KMP算法

最新推荐文章于 2020-10-06 10:15:08 发布

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最新推荐文章于 2020-10-06 10:15:08 发布

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分类专栏：数据结构与算法文章标签：算法 string class application input

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using System;

namespace kmp
{
    /// <summary>
    /// Summary description for Class1.
    /// </summary>
    class Class1
    {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        static int[] next = new int[20];
        static int count = 0;
        static int kmp(char[] a, char[] b, int pos)
        {
            int i = pos, j = 0;
            int lena = a.Length, lenb = b.Length;
            count = 0;
            while ((i <= lena - 1) && (j <= lenb - 1))
            {
                if (a[i] == b[j])
                { ++i; ++j; }
                else
                { i = i - j + 1; j = 0; }
                count++;
            }
            if (j > lenb - 1)
                return i - lenb;
            else
                return 0;
        }
        [STAThread]
        static void Main(string[] args)
        {
            //
            // TODO: Add code to start application here
            //
            int pos = 0, reval;
            Console.WriteLine("input string1");
            string s1 = Console.ReadLine();
            Console.WriteLine("input string2");
            string s2 = Console.ReadLine();
            char[] p1 = s1.ToCharArray();
            char[] p2 = s2.ToCharArray();
            Console.WriteLine("lena={0},lenb={1}", p1.Length, p2.Length);
            reval = kmp(p1, p2, pos);
            Console.WriteLine("====not kmp ====");
            Console.WriteLine("value={0},count={1}", reval, count);
            get_next(p2, next);
            reval = index_kmp(p1, p2, pos);
            Console.WriteLine("====this is kmp ====");
            Console.WriteLine("value={0},count={1}", reval, count);
            get_goodnext(p2, next);
            reval = index_kmp(p1, p2, pos);
            Console.WriteLine("====this is good kmp ====");
            Console.WriteLine("value={0},count={1}", reval, count);
            Console.ReadLine();
        }
        static int index_kmp(char[] a, char[] b, int pos)
        {
            int i = pos, j = 0;
            int lena = a.Length, lenb = b.Length;
            count = 0;
            while ((i <= lena - 1) && (j <= lenb - 1))
            {
                if (j == 0 || a[i] == b[j])
                { ++i; ++j; }
                else
                { j = next[j]; }
                count++;
            }
            if (j > lenb - 1)
                return i - lenb;
            else
                return 0;
        }
        static void get_next(char[] a, int[] next)
        {
            int i = 1, j = 0;
            next[0] = 0;
            while (i <= a.Length - 2)
            {
                if (j == 0 || a[i] == a[j])
                { ++i; ++j; next[i] = j; }
                else
                { j = next[j]; }
            }
        }
        static void get_goodnext(char[] a, int[] next)
        {
            int i = 1, j = 0;
            next[0] = 0;
            while (i <= a.Length - 2)
            {
                ++i; ++j;
                if (j == 0 || a[i] == a[j])
                {
                    if (a[i] != a[j])
                    {
                        next[i] = j;
                    }
                    else
                    {
                        next[i] = next[j];
                    }
                }
                else
                { j = next[j]; }
            }
        }
    }
}