夏令营

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cctype>
#define LL long long
using namespace std;
const int M=45007,N=1<<17; 
int read()
{
    char c;int s=0,t=1;
    while(!isdigit(c=getchar()))if(c==‘-‘)t=-1;
    do{s=s*10+c-‘0‘;}while(isdigit(c=getchar()));
    return s*t;
}
int T,n,m,c[M],cnt,L,R;
int f[M],last[M];
struct node{int v,pos;}e[M];
struct note{int h,mx;}tr[N];
bool cmp(node a,node b){return a.v<b.v;}
int max(int a,int b){return a>b?a:b;}
inline void up(int x){tr[x].mx=max(tr[x<<1].mx,tr[x<<1^1].mx);}
void build(int x,int l,int r){
    tr[x].h=0;
    if(l==r){
        tr[x].mx=f[l-1];
        return ;
    }
    int mid=(l+r)>>1;
    build(x<<1,l,mid);
    build(x<<1^1,mid+1,r);
    up(x);
}
void modify(int x,int l,int r){
    note&w=tr[x];
    if(L<=l&&r<=R){
        ++w.mx;
        ++w.h;
        return ;
    }
    note&lc=tr[x<<1],&rc=tr[x<<1^1];
    if(w.h){
        int a=w.h;
        lc.mx+=a;
        lc.h+=a;
        rc.mx+=a;
        rc.h+=a;
        w.h=0;
    }
    int mid=(l+r)>>1;
    if(L<=mid) modify(x<<1,l,mid);
    if(R>mid) modify(x<<1^1,mid+1,r);
    w.mx=max(lc.mx,rc.mx);
}
void push_max(int x,int l,int r){
    note&w=tr[x];
    if(w.mx<=T) return ;
    if(L<=l&&r<=R) return void(T=w.mx);
    if(w.h){
        note&lc=tr[x<<1],&rc=tr[x<<1^1];
        int a=w.h;
        lc.mx+=a;
        lc.h+=a;
        rc.mx+=a;
        rc.h+=a;
        w.h=0;
    }
    int mid=(l+r)>>1,ans=0;
    if(L<=mid) push_max(x<<1,l,mid);
    if(R>mid)  push_max(x<<1^1,mid+1,r);
}
int main()
{
    freopen("camp.in","r",stdin);
    freopen("camp.out","w",stdout);
    scanf("%d %d",&n,&m);
    for(int i=1;i<=n;i++) e[i].v=read(),e[i].pos=i;
    sort(e+1,e+1+n,cmp);
    c[e[1].pos]=++cnt;
    for(int i=2;i<=n;i++){
        if(e[i].v!=e[i-1].v) cnt++;
        c[e[i].pos]=cnt;
    }
    for(int k=1;k<=m;k++){
        build(1,1,n);
        memset(last,0,sizeof(last));
        for(int i=1;i<=n;i++){
            L=last[c[i]]+1; R=i;
            modify(1,1,n);
            L=1; R=i;
            T=0;
            push_max(1,1,n);
            f[i]=T;
            last[c[i]]=i;
        }
    }printf("%d\n",f[n]);
    return 0;
}