文章目录
kmp中的nextVal（代码用next数组表示）
cs
namespace Testmain
{
public class GetNext
{
int[] next;
public int[] getNextArray(char[] ch)
{
next = new int[ch.Length];
int i = 0, j = -1;
next[0] = -1;
while (i < ch.Length - 1)
{
if (j == -1 || ch[i] == ch[j])
{
i++;
j++;
if (ch[i] != ch[j])
{
next[i] = j;
}
else
{
next[i] = next[j];
}
}
else
{
j = next[j];
}
}
return next;
}
}
}获取匹配成功的主串下标
cs
namespace Testmain
{
public class Index_KMP
{
public int getIndex(char[] S, char[] T)
{
int i = 0;//main string
int j = 0;//model string
int[] next = new int[255];
GetNext getNext = new GetNext();
next = getNext.getNextArray(T);
while (i <= S.Length - 1 && j <= T.Length - 1)
{
if (j == -1 || S[i] == T[j])
{
++i;
++j;
}
else
{
j = next[j];
}
}
if (j > T.Length - 1)
{
return i - j;
}
else
{
return 0;
}
}
}
}程序入口（示例）
cs
using System;
namespace Testmain
{
class Program
{
static void Main(string[] args)
{
try
{
char[] S = { 'w', 'a', 'b', 'a', 'b', 'a', 'b', 'a', 'a', 'a', 'b', 'a', 'm' };
char[] chars = { 'a', 'b', 'a', 'b', 'a', 'a', 'a', 'b', 'a' };
Index_KMP index_KMP = new Index_KMP();
var A = index_KMP.getIndex(S, chars);
Console.WriteLine(A);
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
}
}
}