hdu1686 Oulipo【kmp】

#include <algorithm>
#include <cstdio>
#include <cstring>
#include <iostream>
using namespace std;
const int maxn = 1000000+100;
char a[maxn],b[maxn];
int nex[maxn];
void getNex(char a[])
{
int len = strlen(a);
memset(nex,-1,sizeof(-1));
int k = -1,i = 0;
while(i<len)
{
if(k==-1 || a[k]==a[i])
{
k++,i++;
nex[i] = k;
}
else
k = nex[k];
}
}
int kmp_cnt(char a[],char b[])
{
int len1 = strlen(a),len2 = strlen(b);
int i=0,j=0;
int cnt = 0;
getNex(b);
while(i<len1 && j<len2)
{
if(a[i]==b[j])
{
i++;
j++;
if(j==len2)
{
cnt++;
j =nex[j];
}
}
else if(j==0)
i++;
else
j = nex[j];
}
return cnt;
}
int main(void)
{
int t;
cin>>t;
while(t--)
{
scanf("%s %s",b,a);
int ans = kmp_cnt(a,b);
printf("%d\n",ans);
}

return 0;
}