【BZOJ】【2253】【WC 2010 BeijingWC】纸箱堆叠

树套树

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　　Orz zyf

　　我的树套树不知道为啥一直WA……只好copy了zyf的写法TAT

　　这题还可以用CDQ分治来做……但是蒟蒻不会……

//y坐标的树状数组是按权值建的……所以需要离散化……

 /**************************************************************
     Problem: 2253
     User: Tunix
     Language: C++
     Result: Accepted
     Time:2808 ms
     Memory:76280 kb
 ****************************************************************/

 //BZOJ 2253
 #include<cmath>
 #include<vector>
 #include<cstdio>
 #include<cstring>
 #include<cstdlib>
 #include<iostream>
 #include<algorithm>
 #define rep(i,n) for(int i=0;i<n;++i)
 #define F(i,j,n) for(int i=j;i<=n;++i)
 #define D(i,j,n) for(int i=j;i>=n;--i)
 #define pb push_back
 #define CC(a,b) memset(a,b,sizeof(a))
 using namespace std;
 int getint(){
     int v=,sign=; char ch=getchar();
     while(!isdigit(ch)) {if(ch=='-') sign=-; ch=getchar();}
     while(isdigit(ch))  {v=v*+ch-''; ch=getchar();}
     return v*sign;
 }
 const int N=,M=,INF=~0u>>;
 typedef long long LL;
 const double eps=1e-;
 /*******************template********************/
 int n,tot,l[M],r[M],s[M],rnd[M],v[M],f[N],mx[M];
 #define L l[x]
 #define R r[x]
 inline void Push_up(int x){ mx[x]=max(max(mx[L],mx[R]),s[x]); }
 inline void zig(int &x){int t=L; L=r[t]; r[t]=x; Push_up(x); Push_up(t); x=t;}
 inline void zag(int &x){int t=R; R=l[t]; l[t]=x; Push_up(x); Push_up(t); x=t;}
 void ins(int &x,int val,int num){
     if (!x){
         x=++tot; v[x]=val; s[x]=mx[x]=num; L=R=; rnd[x]=rand(); return;
     }
     if(v[x]==val) s[x]=max(s[x],num);
     else if(val<v[x]){
         ins(L,val,num); if (rnd[L]<rnd[x]) zig(x);
     }else{
         ins(R,val,num); if (rnd[R]<rnd[x]) zag(x);
     }
     Push_up(x);
 }
 int rank(int x,int val){
     if (!x) return ;
     if (v[x]==val) return max(mx[L],s[x]);
     else if (val<v[x]) return rank(L,val);
     else return max(max(s[x],mx[L]),rank(R,val));
 }
 #undef L
 #undef R
 /********************Treap**********************/
 int rt[N],_num,b[N],c[N],d[N];
 void update(int x,int val,int num){
     for(int i=x;i<=_num;i+=i&-i) ins(rt[i],val,num);
 }
 int query(int x,int val){
     int ans=;
     for(int i=x;i;i-=i&-i) ans=max(ans,rank(rt[i],val));
     return ans;
 }
 /*******************Fenwick*********************/
 struct data{
     int x,y,z;
 }a[N];
 bool cmp(data a,data b){
     return a.x<b.x;
 }
 bool cmp2(int x,int y){return b[x]>b[y];}
 void init(){
     LL A=getint(),P=getint();
     n=getint();
     b[]=;
     F(i,,n*) b[i]=(LL)b[i-]*A%P,c[i]=i;
     sort(c+,c+*n+,cmp2);
     _num=;
     F(i,,*n){
         if (i== || b[c[i]]!=b[c[i-]]) _num++;
         d[c[i]]=_num;
     }
     F(i,,n) a[i].x=d[*i-],a[i].y=d[*i-],a[i].z=d[*i];
     F(i,,n){
         if (a[i].y>a[i].x) swap(a[i].x,a[i].y);
         if (a[i].z>a[i].x) swap(a[i].x,a[i].z);
         if (a[i].z>a[i].y) swap(a[i].y,a[i].z);
     }
     sort(a+,a+n+,cmp);
 }
 int main(){
 #ifndef ONLINE_JUDGE
     freopen("input.txt","r",stdin);
 //  freopen("output.txt","w",stdout);
 #endif
     init();
     int ans=;
     for(int l=,r=;l<=n;r++,l=r){
         while(a[r+].x==a[l].x) r++;
         F(i,l,r) f[i]=query(a[i].y-,a[i].z-)+;
         F(i,l,r) update(a[i].y,a[i].z,f[i]);
     }
     F(i,,n) ans=max(f[i],ans);
     printf("%d\n",ans);
     return ;
 }
 //y坐标的树状数组是按权值建的……所以需要离散化……