[BZOJ3781]小B的询问

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cctype>
#include <algorithm>
#include <vector>
#include <cmath>
using namespace std;

int read() {
	int x = 0, f = 1; char c = getchar();
	while(!isdigit(c)){ if(c == ‘-‘) f = -1; c = getchar(); }
	while(isdigit(c)){ x = x * 10 + c - ‘0‘; c = getchar(); }
	return x * f;
}

#define maxn 50010
#define maxbl 233
#define LL long long

int A[maxn];
struct Que {
	int l, r;
	Que() {}
	Que(int _, int __): l(_), r(__) {}
} qs[maxn];

bool cmp(int a, int b) { return qs[a].r < qs[b].r; }
vector <int> qid[maxbl];
int tot[maxn];
LL Ans[maxn];

LL sqr(int x) { return (LL)x * x; }

int main() {
	int n = read(), q = read(), K = read();
	for(int i = 1; i <= n; i++) A[i] = read();
	
	int m = sqrt(n + .5), cntb = 0;
	for(int i = 1; i <= q; i++) {
		int l = read(), r = read();
		qs[i] = Que(l, r);
		qid[(l-1)/m+1].push_back(i);
		cntb = max(cntb, (l - 1) / m + 1);
	}
	for(int i = 1; i <= cntb; i++) {
		sort(qid[i].begin(), qid[i].end(), cmp);
		memset(tot, 0, sizeof(tot));
		int l = 1, r = 0; LL ans = 0;
		for(vector <int> :: iterator j = qid[i].begin(); j != qid[i].end(); j++) {
			while(r < qs[*j].r) tot[A[++r]]++, ans = ans - sqr(tot[A[r]] - 1) + sqr(tot[A[r]]);
			while(l < qs[*j].l) tot[A[l]]--, ans = ans - sqr(tot[A[l]] + 1) + sqr(tot[A[l]]), l++;
			while(l > qs[*j].l) tot[A[--l]]++, ans = ans - sqr(tot[A[l]] - 1) + sqr(tot[A[l]]);
			Ans[*j] = ans;
		}
	}
	
	for(int i = 1; i <= q; i++) printf("%lld\n", Ans[i]);
	
	return 0;
}