hdu 3874 Necklace

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线段树

跟三鲜图灵树一模一样的题目，不过数据小一些，省掉了离散化

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#include <iostream>
#include <cstdio>
#include <cstring>
#include <vector>
using namespace std;
#define N 50010
#define M 200010
#define MAX 1000010
#define LL long long 
#define cl(xx,yy) memset((xx),(yy),sizeof((xx)))
#define pb push_back

LL c[N];
int n,num[N],pre[MAX];
struct ASK{
	int l,r;
	LL res;
}ask[M];
vector<int>List[N];

inline int lowbit(int x){
	return x & (-x);
}

void add(int pos,LL val){
	while(pos <= n){
		c[pos] += val; pos += lowbit(pos);
	}
}

LL sum(int pos){
	LL res = 0;
	while(pos){
		res += c[pos]; pos -= lowbit(pos);
	}
	return res;
}

int main(){
	int q,cas;
	scanf("%d",&cas);
	while(cas--){
		scanf("%d",&n);
		for(int i = 1; i <= n; i++)
			scanf("%d",&num[i]);
		scanf("%d",&q);
		for(int i = 1; i <= n; i++)
			List[i].clear();
		for(int i = 0; i < q; i++){
			scanf("%d%d",&ask[i].l,&ask[i].r);
			List[ask[i].r].pb(i);
		}
		cl(pre,-1); cl(c,0);
		for(int i = 1; i <= n; i++){
			if(pre[num[i]] != -1)
				add(pre[num[i]],-num[i]);
			add(i,num[i]);
			pre[num[i]] = i;
			if(!List[i].empty()){
				for(int k = 0; k < List[i].size(); k++){
					int id = List[i][k];
					ask[id].res = sum(ask[id].r) - sum(ask[id].l - 1);
				}
			}
		}
		for(int i = 0; i < q; i++)
			printf("%I64d\n",ask[i].res);
	}
	return 0;
}