1 char *strstr(const char*s1,const char*s2)
 2 {
 3     const char*p=s1;
 4     const size_t len=strlen(s2);
 5     for(;(p=strchr(p,*s2))!=0;p++)
 6     {
 7         if(strncmp(p,s2,len)==0)
 8             return (char*)p;
 9     }
10     return(0);
11 }

  1 #include <string.h>
  2 #include <stdio.h>
  3
  4 #define LIB_MATCH_NUM  5
  5 #define LIB_STRING_LEN 40
  6
  7 char lib_match[LIB_MATCH_NUM][LIB_STRING_LEN] =
  8 {
  9     "www.baidu.comw",
 10     "www.google.com",
 11     "www",
 12     "baidu.com",
 13     "lualu",
 14 };
 15
 16 int lib_match_len[LIB_MATCH_NUM];
 17
 18 int lib_match_next[LIB_MATCH_NUM][LIB_STRING_LEN + 1] = {0};
 19
 20
 21 void get_next();
 22
 23 void lib_match_init()
 24 {
 25     memset(lib_match_len,0,sizeof(lib_match_len));
 26     int i;
 27     for(i = 0; i < LIB_MATCH_NUM; i++)
 28     {
 29         lib_match_len[i] = strlen(lib_match[i]);
 30     }
 31
 32     get_next(); // init next array
 33 }
 34
 35 void get_next()
 36 {
 37     int i,j,k;
 38
 39     for(i = 0; i < LIB_MATCH_NUM; i++)
 40     {
 41
 42         lib_match_next[i][0] = 0;
 43         lib_match_next[i][1] = 0;
 44
 45         k = 0; //point to the last next[j]
 46         int len = lib_match_len[i];
 47
 48         for( j = 1; j < len; j++)
 49         {//j start from 1 because next start from 2
 50             k = lib_match_next[i][j]; //k = next[j];
 51
 52             while(k > 0 && lib_match[i][j] != lib_match[i][k])
 53             {
 54                 k = lib_match_next[i][k];
 55             }
 56
 57             if(lib_match[i][j] == lib_match[i][k])
 58             {//s[j] == s[next[k]] next[i+1] = next[k] +1
 59                 k++;
 60             }
 61
 62             lib_match_next[i][j+1] = k;
 63         }
 64
 65     }
 66
 67 }
 68
 69 int lib_search(char *orignal,int len)
 70 {
 71     if(orignal == NULL)
 72     {
 73         return 0;
 74     }
 75
 76     int i,j,k;
 77
 78     for(i = 0; i < LIB_MATCH_NUM; i++)
 79     {
 80         char *tmp = orignal; // match each model need to start from the first
 81         k = 0; // k start from the last next array
 82
 83         for(j = 0; j < len; j++)
 84         {
 85
 86             while( k > 0 && tmp[j] != lib_match[i][k])
 87             {
 88                 k = lib_match_next[i][k];
 89             }
 90
 91             if(tmp[j] == lib_match[i][k])
 92             {
 93                 k++;
 94             }
 95
 96             if(k == lib_match_len[i])
 97             {
 98                 printf("match the model string %d : %s\n", i,lib_match[i]);
 99                 printf("match at the position  :%d\n\n", j - lib_match_len[i] + 1);
100
101                 // here can return the i to know which model string have been matched
102
103                 k = lib_match_next[i][k]; //to match another this model string
104             }
105
106         }
107
108     }
109
110     return 0;
111 }
112
113 void print_next()
114 {
115     int i,j;
116
117     for(i = 0; i < LIB_MATCH_NUM; i++)
118     {
119         printf("model string : %s \n",lib_match[i]);
120         printf("next array:");
121         for(j = 0; j < lib_match_len[i]+1;j++)
122         {
123             printf(" %d",lib_match_next[i][j]);
124         }
125         printf("\n\n");
126     }
127 }
128
129
130 int main()
131 {
132     char orignal[40];
133
134     lib_match_init();
135
136     print_next();
137
138     while(1)
139     {
140
141         scanf("%s",orignal);
142
143         if(strcmp(orignal,"0") == 0)
144         {
145             return 0;
146         }
147
148         lib_search(orignal,strlen(orignal));
149     }
150
151     return 0;
152
153 }