字符串匹配算法是一种高效率的字符串匹配算法，在面试中，经常会被问及到，考官经常会考察我们，代码如下：
int[] nextKMP(string str)
{
int[] next = new int[str.Length];
next[0] = -1;
if (str.Length < 2)
return next;
next[1] = 0;
int i = 2, j = 0;
while(i < str.Length)
{
if(str[i-1] == str[j]){
next[i++] = ++j;
}else{
j = next[j];
if(j == -1){
next[i++] = ++j;
}
}
}
return next;
}
int executeKMP(string source, string pattern)
{
int[] next = nextKMP(pattern);
int i = 0, j = 0;
while (j < pattern.Length && i < source.Length)
{
if (source[i] == pattern[j])
{
i++;
j++;
}
else
{
j = next[j];
if (j == -1)
{
i++;
j++;
}
}
}
return j < pattern.Length ? -1 : i - j;
}
