题目:
分析:
字符串哈希模版,不多说
代码:
#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<cstdlib>
#include<algorithm>
#include<set>
#include<queue>
#include<vector>
#include<map>
#include<list>
#include<ctime>
#include<iomanip>
#include<string>
#include<bitset>
#include<deque>
#include<set>
#define XJQ 1000000007
#define base 80
#define base2 30
#define LL long long
using namespace std;
inline LL read() {
LL d=0,f=1;char s=getchar();
while(s<'0'||s>'9'){if(s=='-')f=-1;s=getchar();}
while(s>='0'&&s<='9'){d=d*10+s-'0';s=getchar();}
return d*f;
}
char c[201000];
LL p[201000], p2[201000];
map<LL,LL> wyc;
map<LL,LL> king;
int main()
{
LL n=read(),m=read();
cin>>c+1;
for(LL i=1;i<=n;i++) p[i]=(p[i-1]*base+c[i]-'a'+1)%XJQ;
for(LL i=1;i<=n;i++) p2[i]=(p2[i-1]*base2+c[i]-'a'+1)%XJQ;
LL y=1,y2=1;
for(LL i=1;i<=m;i++) y=y*base%XJQ,y2=y2*base2%XJQ;
LL ans=0;
for(LL i=1;i+m-1<=n;i++)
{
LL o=(p[i+m-1]-p[i-1]*y%XJQ+XJQ)%XJQ;
LL o2=(p2[i+m-1]-p2[i-1]*y2%XJQ+XJQ)%XJQ;
if(!wyc[o]||!king[o2]) ans++;
wyc[o]=king[o2]=1;
}
printf("%d",ans);
return 0;
}