HDU 3333 & 主席树

题意:

　　balabala

SOL:

　　这题用主席树怎么做呢...貌似一模一样...一个一个建n棵的线段树.先把上一棵树复制下来,当a[i]出现过,就把这棵树里的那个位置去掉------一模一样的思维...就是用空间换时间达到在线罢了...然而他的在线比我的离线还快是什么鬼...线段树果然比树状数组慢不止一点点啊...

CODE:

#include <cstdio>
#include <cstring>
#include <cctype>
#include <cmath>
#include <set>
#include <unordered_map>
#include <queue>
#include <stack>
#include <vector>
#include <string>
#include <algorithm>
using namespace std;
typedef long long LL;
#define rep(i,a,n) for(int i = a; i < n; i++)
#define repe(i,a,n) for(int i = a; i <= n; i++)
#define per(i,n,a) for(int i = n; i >= a; i--)
#define clc(a,b) memset(a,b,sizeof(a))
const int INF = 0x3f3f3f3f, MAXN = 30000+10, MAXM = MAXN*50;
int lc[MAXM],rc[MAXM],tol;
LL sum[MAXM];
int a[MAXN], rt[MAXN];
unordered_map<int,int> vis;
 
void update(int &u, int x, int y, int p, LL v)
{
    sum[tol] = sum[u]+v,lc[tol] = lc[u],rc[tol] = rc[u];
    u = tol++;
    if(x == y) return;
    int m = (x+y)>>1;
    if(p <= m) update(lc[u],x,m,p,v);
    else update(rc[u],m+1,y,p,v);
}
LL query(int u, int x, int y, int ql, int qr)
{
    if(ql <= x && y <= qr) return sum[u];
    int m = (x+y)>>1;
    LL ans = 0;
    if(ql <= m) ans += query(lc[u],x,m,ql,qr);
    if(qr > m) ans += query(rc[u],m+1,y,ql,qr);
    return ans;
}
int main()
{
    int t;
    scanf("%d%*c", &t);
    while(t--)
    {
        int n;
        scanf("%d", &n);
        repe(i,1,n) scanf("%d", &a[i]);
        tol = 1;
        vis.clear();
        repe(i,1,n)
        {
            rt[i] = rt[i-1];
            if(vis.find(a[i]) != vis.end())
            {
                int tmp = rt[i-1];
                update(tmp,1,n,vis[a[i]],-a[i]);
                rt[i] = tmp;
                update(rt[i],1,n,i,a[i]);
            }
            else
            {
                rt[i] = rt[i-1];
                update(rt[i],1,n,i,a[i]);
            }
            vis[a[i]] = i;
        }
        int q;
        scanf("%d", &q);
        rep(i,0,q)
        {
            int x,y;
            scanf("%d %d", &x, &y);
            printf("%I64d\n", query(rt[y],1,n,x,y));
        }
    }
    return 0;
}