3289. Mato的文件管理【莫队+树状数组】

 1 #include<iostream>
 2 #include<cstring>
 3 #include<cstdio>
 4 #include<cmath>
 5 #include<algorithm>
 6 #define N (1000000+1000)
 7 using namespace std;
 8 
 9 int c[N],a[N],n,m,unit,Ans;
10 
11 struct Que{int x,y,id,num,ans;}Q[N];
12 bool cmp1(Que a,Que b){return a.id<b.id || a.id==b.id && a.y<b.y;}
13 bool cmp2(Que a,Que b){return a.num<b.num;}
14 
15 int lowbit(int x){return x & -x;}
16 void Update(int x,int v){for (;x<=1000000; c[x]+=v,x+=lowbit(x));}
17 int Query(int x){int s=0; for (;x; s+=c[x],x-=lowbit(x)); return s;}
18 
19 void Del(int x,int dir)
20 {
21     if (dir==-1) Ans-=Query(a[x]-1),Update(a[x],-1);
22     else Ans-=Query(1000000)-Query(a[x]),Update(a[x],-1);
23 }
24 
25 void Ins(int x,int dir)
26 {
27     if (dir==-1) 
28         Ans+=Query(a[x]-1),Update(a[x],1);
29     else 
30         Ans+=Query(1000000)-Query(a[x]),Update(a[x],1);
31 }
32 
33 int main()
34 {
35     scanf("%d",&n); unit=sqrt(n);
36     for (int i=1; i<=n; ++i)
37         scanf("%d",&a[i]);
38     scanf("%d",&m);
39     for (int i=1; i<=m; ++i)
40     {
41         scanf("%d%d",&Q[i].x,&Q[i].y);
42         Q[i].num=i; Q[i].id=Q[i].x/unit;
43     }
44     sort(Q+1,Q+m+1,cmp1);
45     
46     int l=1, r=0;
47     for (int i=1; i<=m; ++i)
48     {
49         while (l<Q[i].x) Del(l++,-1);
50         while (l>Q[i].x) Ins(--l,-1);
51         while (r<Q[i].y) Ins(++r,1);
52         while (r>Q[i].y) Del(r--,1);
53         Q[i].ans=Ans;
54     }
55     sort(Q+1,Q+m+1,cmp2);
56     for (int i=1; i<=m; ++i)
57         printf("%d\n",Q[i].ans);
58 }