POJ Oulipo (KMP)

题目大意 : 在一个字符串中找出目标单词的个数

代码:

      #include<iostream>
      #include<cstdio>
      #include<cstdlib>
      #include<cstring>
      #include<queue>
      #include<algorithm>
      #include<cmath>
      #include<map>
      using namespace std;
      #define INF 0x7fffffff

      char t[1000010],w[10010];
      int next[10010];
      void getnext(int wlen){
	      int i,j;
	      next[0] = 0;
	      next[1] = 0;
	      for(i=1;i<wlen;i++){
		      j = next[i];
		      while(j && w[i] != w[j]) j = next[j];
		      if(w[i] == w[j]) next[i+1] = j+1 ;
		      else   next[i+1] = 0 ;
 	      }
      }

      int KMP(){
	      int i,j,tlen,wlen,cnt = 0;
	      tlen = strlen(t);
	      wlen = strlen(w);
	      j = 0;
	      getnext(wlen);
	      for(i=0;i<tlen;i++){
		      while(j && w[j] != t[i]) j = next[j];
		      if(w[j] == t[i]) j++;
		      if(j>=wlen)
		          cnt ++;
	      }
	      return cnt ;
      }

      int main(){
	      int  i,j,n,cnt;
	      cin >> n;
	      for(i=1;i<=n;i++){
		      scanf("%s%s",w,t);
		      printf("%d\n",KMP());
	      }  

	      return 0;
      }