bzoj3781 小B的询问(莫队)

来源：互联网发布：python自然语言处理库编辑：程序博客网时间：2024/05/17 03:00

赤裸裸的莫队。

#include <cstdio>#include <cstring>#include <algorithm>#include <cmath>#define N 50005using namespace std;int n,m,k,a[N],f[N],ans=0,block=0,ANS[N];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;}struct query{int l,r,block,id;}q[N];inline bool cmp(query x,query y){return x.block==y.block?x.r<y.r:x.block<y.block;}bool vis[N];void change(int x){ans-=f[a[x]]*f[a[x]];if(vis[x]) f[a[x]]--;else f[a[x]]++;vis[x]^=1;ans+=f[a[x]]*f[a[x]];}int main(){//freopen("a.in","r",stdin);n=read();m=read();k=read();block=sqrt(n);for(int i=1;i<=n;++i) a[i]=read();for(int i=1;i<=m;++i){q[i].l=read();q[i].r=read();q[i].id=i;q[i].block=(q[i].l-1)/block;}sort(q+1,q+m+1,cmp);int l=1,r=0;for(int i=1;i<=m;++i){for(;l<q[i].l;++l) change(l);for(;l>q[i].l;--l) change(l-1);for(;r<q[i].r;++r) change(r+1);for(;r>q[i].r;--r) change(r);ANS[q[i].id]=ans;}for(int i=1;i<=m;++i) printf("%d\n",ANS[i]);return 0;}

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