3781: 小B的询问 莫队算法

裸的莫队qwq。。

#include<iostream>#include<cstdio>#include<algorithm>#include<cmath>#define ll long long using namespace std;int n,m,k;ll ans,s[50005];int pos[50005],c[50005];struct node {int l,r,id; ll ans;} a[50005];inline int read(){    int a=0,f=1; char c=getchar();    while (c<'0'||c>'9') {if (c=='-') f=-1; c=getchar();}    while (c>='0'&&c<='9') {a=a*10+c-'0'; c=getchar();}    return a*f;}ll sqr(ll x){    return x*x;}inline bool cmp(node a,node b){    return pos[a.l]==pos[b.l]?a.r<b.r:a.l<b.l;}inline bool cmp0(node a,node b){    return a.id<b.id;}inline void update(int p,int add){    ans-=sqr(s[c[p]]);    s[c[p]]+=add;    ans+=sqr(s[c[p]]);}int main(){    n=read(); m=read(); k=read();    for (int i=1;i<=n;i++) c[i]=read();    for (int i=1;i<=m;i++)        a[i].l=read(),a[i].r=read(),a[i].id=i;    int block=(int)(sqrt(n));    for (int i=1;i<=n;i++) pos[i]=(i-1)/block+1;    sort(a+1,a+m+1,cmp);    int l=1,r=0;    for (int i=1;i<=m;i++)    {        for (;r<a[i].r;r++) update(r+1,1);        for (;r>a[i].r;r--) update(r,-1);        for (;l<a[i].l;l++) update(l,-1);        for (;l>a[i].l;l--) update(l-1,1);        a[i].ans=ans;    }    sort(a+1,a+m+1,cmp0);    for (int i=1;i<=m;i++) printf("%lld\n",a[i].ans);    return 0;}