P1972-[SDOI2009]HH的项链

 1 #include <bits/stdc++.h>
 2 typedef long long ll;
 3 using namespace std;
 4 #define _for(i,a,b) for(int i = (a);i < b;i ++)
 5 #define _rep(i,a,b) for(int i = (a);i > b;i --)
 6 #define INF 0x3f3f3f3f
 7 #define MOD 1000000007
 8 #define pb push_back
 9 #define maxn 100003
10 inline ll read()
11 {
12     ll ans = 0;
13     char ch = getchar(), last = ' ';
14     while(!isdigit(ch)) last = ch, ch = getchar();
15     while(isdigit(ch)) ans = (ans << 1) + (ans << 3) + ch - '0', ch = getchar();
16     if(last == '-') ans = -ans;
17     return ans;
18 }
19 inline void write(ll x)
20 {
21     if(x < 0) x = -x, putchar('-');
22     if(x >= 10) write(x / 10);
23     putchar(x % 10 + '0');
24 }
25 
26 struct q
27 {
28     int l;
29     int r;
30     int id;
31     bool operator < (q b)
32     {
33         return r < b.r;
34     }
35 };
36 int c[1000003];
37 int N,R;
38 int ask(int x)
39 {
40     int ans = 0;
41     for(; x; x -= x&-x) ans += c[x];
42     return ans;
43 }
44 void add(int x,int y)
45 {
46     for(; x <= N; x += x & -x) c[x]+=y;
47 }
48 
49 q Q[1000003];
50 int num[1000003];
51 int ans[1000003];
52 int H[1000003];
53 int pre[1000003];
54 int main()
55 {
56     N = read();
57     _for(i,1,N+1)
58     num[i] = read();
59     R = read();
60     _for(i,1,R+1)
61     {
62         Q[i].l = read();
63         Q[i].r = read();
64         Q[i].id = i;
65     }
66     sort(Q+1,Q+R+1);
67     int j = 1;
68     _for(i,1,R+1)
69     {
70         while(j<=Q[i].r)
71         {
72             if(!H[num[j]])
73             {
74                 H[num[j]] = 1;
75                 pre[num[j]] = j;
76             }
77             else
78             {
79                 add(pre[num[j]],-1);
80                 pre[num[j]] = j;
81             }
82             add(j,1);
83             j ++;
84         }
85         ans[Q[i].id] = ask(Q[i].r)-ask(Q[i].l-1);
86     }
87     _for(i,1,R+1)
88         printf("%d\n",ans[i]);
89     return 0;
90 }