#include<stdio.h> #include<stdlib.h> #include<string.h> int *GetNext(char *match) {     int i;     i = 1;     int *pNext = NULL;     pNext = (int*)malloc(sizeof(int)*strlen(match));     pNext[0] = 0;     int j;     j = i-1;     while(i < strlen(match))     {         if(match[i] == match[pNext[j]])         {             pNext[i] = pNext[j]+1;             i++;             j = i-1;         }         else if(pNext[j] == 0)         {             pNext[i] = 0;             i++;             j = i-1;         }         else         {             j = pNext[j]-1;         }     }     return pNext; } int KMP(char *src,char *match) {     if(src == NULL || match == NULL)return -1;     int *pNext = NULL;     //获得Next数组     pNext = GetNext(match);     //查找     int i;     int j;     i = 0;     j = 0;     while(i < strlen(src)&& j<strlen(match))     {         if(src[i] == match[j])         {             i++;             j++;         }         else         {             //不想等 且匹配串已经回到开始位置仍不相等 主串向后移动             if(j == 0)             {                 i++;             }             //匹配串向前移动             else             {                 j = pNext[j-1];             }         }     }     //匹配串已经走完  结束     if(j == strlen(match))     {         return i-j;     }     return -1; } int main() {     char *src = "ahfhawoerqhewqlknxcabcabcdabcabcfjfesaruwqou";     char *match = "abcahseifysfryewbcdabcabcf";     int n;     n = KMP(src,match);     printf("%d\n",n);     return 0; }