标签:const 线段 div main vector reg gis code out
当初竟然看成子串了$qwq$,不过老师的$ppt$也错了$qwq$
由于子序列一定是的排列,所以考虑插入$1$到$m$到$n-m+1$到$n$;
如何判断呢?可以用哈希$qwq$;
我们用线段树维护哈希值,合并时用就把左子树的哈希值$x[ls]$在$B$进制下左移$sum[rs]$位,即$x[tr]=x[ls]*p[sum[rs]]+x[rs]$;
此时就可以向上更新哈希值。
#include<cstdio> #include<iostream> #include<algorithm> #include<cstring> #include<cmath> #include<cctype> #include<cstdlib> #include<vector> #include<queue> #include<map> #include<set> #define ull unsigned long long #define ll long long #define R register int #define md ((l+r)>>1) #define ls (tr<<1) #define rs (tr<<1|1) #define pause (for(R i=1;i<=10000000000;++i)) #define OUT freopen("out.out","w",stdout) using namespace std; namespace Fread { static char B[1<<15],*S=B,*D=B; #define getchar() (S==D&&(D=(S=B)+fread(B,1,1<<15,stdin),S==D)?EOF:*S++) inline int g() { R ret=0,fix=1; register char ch; while(!isdigit(ch=getchar())) fix=ch==‘-‘?-1:fix; do ret=ret*10+(ch^48); while(isdigit(ch=getchar())); return ret*fix; } inline bool isempty(const char& ch) {return ch<=36||ch>=127;} inline void gs(char* s) {register char ch; while(isempty(ch=getchar())); do *s++=ch; while(!isempty(ch=getchar()));} }using Fread::g; using Fread::gs; const int B=23,N=200010; int n,m,s[N],a[N],pos[N],ans; ull x[N<<2],sum[N<<2],p[N],cnt,hsh; inline void upd(int tr,int l,int r) { sum[tr]=sum[ls]+sum[rs]; x[tr]=x[ls]*p[sum[rs]]+x[rs]; } inline void change(int tr,int l,int r,int pos,int d) { if(l==r) {sum[tr]+=(d?1:-1); x[tr]=d; return ;} if(pos<=md) change(ls,l,md,pos,d); else change(rs,md+1,r,pos,d); upd(tr,l,r); } signed main() { #ifdef JACK freopen("NOIPAK++.in","r",stdin); #endif m=g(),n=g(); p[0]=1; for(R i=1;i<=m;++i) p[i]=p[i-1]*B; for(R i=1;i<=m;++i) s[i]=g(),hsh=hsh*B+s[i],cnt+=p[i-1]; for(R i=1;i<=n;++i) a[i]=g(),pos[a[i]]=i; for(R i=1;i<=n;++i) { if(i>m) change(1,1,n,pos[i-m],0); change(1,1,n,pos[i],i); R d=i-m; if(d>=0&&x[1]==d*cnt+hsh) ++ans; } printf("%d\n",ans); }
2019.06.15
CF213E Two Permutations 线段树维护哈希值
标签:const 线段 div main vector reg gis code out
原文地址:https://www.cnblogs.com/Jackpei/p/11029377.html