POJ3067 Japan

 1 /**/
 2 #include<iostream>
 3 #include<cstdio>
 4 #include<cmath>
 5 #include<cstring>
 6 #include<algorithm>
 7 using namespace std;
 8 const int mxn=20000;
 9 struct edge{
10     int x,y;
11 }e[mxn*100];
12 int cmp(edge a,edge b){
13     if(a.x!=b.x)return a.x<b.x;
14     return a.y<=b.y;
15 }
16 long long t[mxn];
17 int n,m,k;
18 int a[mxn];
19 inline int lowbit(int x){
20     return x&-x;
21 }
22 void add(int p,int v){
23     while(p<=m){
24         t[p]+=v;
25         p+=lowbit(p);
26     }
27     return;
28 }
29 int sum(int p){
30     int res=0;
31     while(p){
32         res+=t[p];
33         p-=lowbit(p);
34     }
35     return res;
36 }
37 int main(){
38     int T;
39     scanf("%d",&T);
40     int i,j;
41     int cas=0;
42     while(T--){
43         long long ans=0;
44         memset(t,0,sizeof t);
45         scanf("%d%d%d",&n,&m,&k);
46         for(i=1;i<=k;i++) scanf("%d%d",&e[i].x,&e[i].y);
47         sort(e+1,e+k+1,cmp);
48         for(i=1;i<=k;i++){
49             ans+=sum(m)-sum(e[i].y);
50             add(e[i].y,1);
51         }
52         printf("Test case %d: %lld\n",++cas,ans);
53     }
54     return 0;
55 }