1 int* Getnext(char *p,int len_p){//p為模式串 
 2     int *Next = new int[len_p];
 3     Next[0] = -1;
 4     int j = -1,i=0;
 5     while(i < len_p){//自身與自身匹配 
 6         while(j != -1&&p[j]!=p[i])//移動匹配串 
 7             j = Next[j];
 8         j+=1;
 9         Next[++i] = j; 
10     }
11
 
     return Next;
12 }
13 vector<int>* Kmp(char *s,char *p,int len_s,int len_p){//s為主串,p為匹配串 
14     int *Next = Getnext(p,len_p);//求得Next數組    
15     int j = 0;//j為匹配串匹配到的位置
16     vector<int>* ans = new vector<int>();//ans為匹配到的主串的開頭下標位置 
17     for(int i=0;i < len_s;i++){
18         while
 
(j != -1 && s[i] != p[j])
19             j = Next[j];
20         j+=1;
21         if(j == len_p){//匹配串匹配完畢
22             ans->push_back(i - len_p + 1);
23             j = Next[j];//j退回到Next[j] 
24         }
25     } 
26     return ans;
27 }

自寫KMP模板