[bzoj1878][SDOI2009]HH的项链

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cmath>
#define MAXN 50000
#define MN 200000
using namespace std;
inline int read()
{
int x = 0 , f = 1; char ch = getchar();
while(ch < '0' || ch > '9'){ if(ch == '-') f = -1;  ch = getchar();}
while(ch >= '0' && ch <= '9'){x = x * 10 + ch - '0';ch = getchar();}
return x * f;
}

int n,m,size;
int s[MAXN+5],pos[MAXN+5],ans[MN+5];
int num[1000005],kind=0;
struct ques{int l,r,num;}q[MN+5];

bool cmp(ques x,ques y){return pos[x.l]==pos[y.l]?x.r<y.r:pos[x.l]<pos[y.l];}

int main()
{
n=read();
for(int i=1;i<=n;i++)s[i]=read();
m=read();size=sqrt(n);
for(int i=1;i<=n;i++)pos[i]=(i-1)/size+1;
for(int i=1;i<=m;i++)
q[i].l=read(),q[i].r=read(),q[i].num=i;
sort(q+1,q+m+1,cmp);
int l=1,r=1;kind=1;num[s[1]]=1;
for(int i=1;i<=m;i++)
{
while(l<q[i].l) if(!--num[s[l++]]) kind--;
while(r>q[i].r) if(!--num[s[r--]]) kind--;
while(r<q[i].r) if(++num[s[++r]]==1) kind++;
while(l>q[i].l) if(++num[s[--l]]==1) kind++;
ans[q[i].num]=kind;
}
for(int i=1;i<=m;i++) printf("%d\n",ans[i]);
return 0;
}