XTUOJ1247 Pair-Pair 预处理+暴力

#include <cstdio>
#include <iostream>
#include <ctime>
#include <vector>
#include <cmath>
#include <map>
#include <queue>
#include <algorithm>
#include <cstring>
using namespace std;
typedef long long LL;
const int N=1e5+5;
const int INF=0x3f3f3f3f;
const int mod=1e9+7;
struct Node{
int x,y;
}p
;
int a[1005][1005];
int high[1005],low[1005],mid[1005];
LL ret[5];
int main()
{
int n,m;
while(~scanf("%d%d",&n,&m)){
memset(a,0,sizeof(a));
memset(ret,0,sizeof(ret));
memset(high,0,sizeof(high));
memset(low,0,sizeof(low));
memset(mid,0,sizeof(mid));
for(int i=1;i<=n;++i){
scanf("%d%d",&p[i].x,&p[i].y);
++a[p[i].x][p[i].y];
if(p[i].y>p[i].x)++high[p[i].x];
else if(p[i].y==p[i].x)++mid[p[i].x];
else ++low[p[i].x];
}
for(int i=1;i<=m;++i){
low[i]+=low[i-1];
mid[i]+=mid[i-1];
high[i]+=high[i-1];
}
for(int i=1;i<=m;++i)
for(int j=1;j<=m;++j)
a[i][j]+=a[i-1][j]+a[i][j-1]-a[i-1][j-1];
for(int i=1;i<=n;++i){
if(p[i].y>p[i].x){
int tmp=0,t;
t=high[m]-high[p[i].y];
tmp+=t;ret[4]+=t;
t=low[m]-low[p[i].y]+mid[m]-mid[p[i].y];
tmp+=t;ret[3]+=t;
t=high[p[i].y]-high[p[i].y-1];
tmp+=t;ret[3]+=t;
t=high[p[i].y-1]-high[p[i].x];
tmp+=t;ret[3]+=t;
t=a[p[i].x][m]-a[p[i].x][p[i].y];
tmp+=t;ret[3]+=t;
ret[2]+=1ll*(n-tmp);
}
else if(p[i].x==p[i].y){
int tmp=0,t;
t=high[m]-high[p[i].x];
tmp+=t;ret[3]+=t;
t=low[p[i].x]+mid[p[i].x];
tmp+=t;ret[1]+=t;
ret[2]+=1ll*(n-tmp);
}
else {
int tmp=0,t;
t=low[p[i].y]+mid[p[i].y];
tmp+=t;ret[1]+=t;
t=high[m]-high[p[i].y];
tmp+=t;ret[3]+=t;
ret[2]+=1ll*(n-tmp);
}
}
printf("%I64d %I64d %I64d %I64d\n",ret[1],ret[2],ret[3],ret[4]);
}
return 0;
}