SPOJ3267--D-query （树状数组离线操作）

 1 #include <cstdio>
 2 #include <string>
 3 #include <vector>
 4 #include <cstdlib>
 5 #include <cstring>
 6 #include <algorithm>
 7 using namespace std;
 8 
 9 const int maxq = 2e5+10;
10 const int maxn = 3e4+10;
11 int last[1000050];
12 int n,m,c[maxn],ans[200005];
13 struct Node
14 {
15     int l,r,ans,idx;
16     bool operator < (const Node &rhs)const
17     {
18         return r < rhs.r || (r == rhs.r && l < rhs.l);
19     }
20 }Q[maxq];
21 int lowbit(int x)
22 {
23     return x & -x;
24 }
25 void add(int x,int d)
26 {
27     while (x <= maxn)
28     {
29         c[x] += d;
30         x += lowbit(x);
31     }
32 }
33 int sum(int x)
34 {
35     int ans = 0;
36     while (x)
37     {
38         ans += c[x];
39         x -= lowbit(x);
40     }
41     return ans;
42 }
43 int a[maxq];
44 int main(void)
45 {
46     #ifndef ONLINE_JUDGE
47         freopen("in.txt","r",stdin);
48     #endif
49     while (~scanf ("%d",&n))
50     {
51         memset(c,0,sizeof(c));
52         memset(last,-1,sizeof(last));
53         for (int i = 2; i <= n+1; i++)
54             scanf ("%d",a+i);
55         scanf ("%d",&m);
56         for (int i = 0; i < m; i++)
57         {
58             Q[i].idx = i;
59             scanf ("%d%d",&Q[i].l,&Q[i].r);
60             Q[i].l++,Q[i].r++;
61         }
62         sort(Q,Q+m);
63         int pre = 2;
64         for (int i = 0; i < m; i++)
65         {
66             for(int j =  pre; j <= Q[i].r; j++)
67             {
68                 if (~last[a[j]])
69                 {
70                     add(last[a[j]],-1);
71                     add(j,1);
72                 }
73                 else
74                 {
75                     add(j,1);
76                 }
77                 last[a[j]] = j;
78             }
79             ans[Q[i].idx] = sum(Q[i].r) - sum(Q[i].l - 1);
80             pre = Q[i].r+1;
81         }
82         for (int i = 0; i < m; i++)
83             printf("%d\n",ans[i]);
84     }
85     return 0;
86 }