POJ 2481 Cows（树状数组）

 1 #include<iostream>
 2 #include<algorithm>
 3 #include<cstring>
 4 #include<cstdio>
 5 #include<vector>
 6 #include<queue>
 7 #include<cmath>
 8 #include<map>
 9 #include<stack>
10 using namespace std;
11 
12 const int maxn=1e5+5;
13 
14 int n;
15 int c[maxn];
16 int ans[maxn];
17 int MAX;
18 
19 struct node
20 {
21     int l,r,id;
22 }a[maxn];
23 
24 
25 bool cmp(node a,node b)
26 {
27     return a.r>b.r||(a.r==b.r&&a.l<b.l);
28 }
29 
30 int lowbit(int x)
31 {
32     return x&-x;
33 }
34 
35 int sum(int x)
36 {
37     int ret=0;
38     while(x>0)
39     {
40         ret+=c[x];
41         x-=lowbit(x);
42     }
43     return ret;
44 }
45 
46 void add(int x,int d)
47 {
48     while(x<=MAX+1)
49     {
50         c[x]+=d;
51         x+=lowbit(x);
52     }
53 }
54 
55 int main()
56 {
57     //freopen("D:\\input.txt","r",stdin);
58     while(scanf("%d",&n))
59     {
60         if(n==0)  break;
61         memset(c,0,sizeof(c));
62         memset(ans,0,sizeof(ans));
63         MAX=0;
64         for(int i=1;i<=n;i++)
65         {
66             scanf("%d%d",&a[i].l,&a[i].r);
67             a[i].l++; a[i].r++;
68             a[i].id=i;
69             MAX=max(MAX,a[i].r);
70         }
71         sort(a+1,a+1+n,cmp);
72         ans[a[1].id]=0;
73         add(a[1].l,1);
74         for(int i=2;i<=n;i++)
75         {
76             if(a[i].l==a[i-1].l && a[i].r==a[i-1].r)   ans[a[i].id]=ans[a[i-1].id];
77             else
78             {
79                 ans[a[i].id]=sum(a[i].l);
80             }
81             add(a[i].l,1);
82         }
83         for(int i=1;i<=n;i++)
84         {
85             if(i!=1)   printf(" ");
86             printf("%d",ans[i]);
87         }
88         printf("\n");
89     }
90     return 0;
91 }