Two priority queues, and then use two arrays to store the values that have been popped, checking each other for popped values.
lld WA'd once
//============================================================================
// Name : Hoax or what.cpp
// Date : 2013/5/12 1:56:32 PM
// Author : GCA
//============================================================================
#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <climits>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <cctype>
#include <utility>
using namespace std;
#ifdef ONLINE\_JUDGE
#define ll "%lld"
#else
#define ll "%I64d"
#endif
typedef unsigned int uint;
typedef long long int Int;
#define Set(a,s) memset(a,s,sizeof(a))
#define Write(w) freopen(w,"w",stdout)
#define Read(r) freopen(r,"r",stdin)
#define Pln() printf("\\n")
#define I\_de(x,n)for(int i=0;i<n;i++)printf("%d ",x\[i\]);Pln()
#define De(x)printf(#x"%d\\n",x)
#define For(i,x)for(int i=0;i<x;i++)
#define CON(x,y) x##y
#define Pmz(dp,nx,ny)for(int hty=0;hty<ny;hty++){for(int htx=0;htx<nx;htx++){\\
printf("%d ",dp\[htx\]\[hty\]);}Pln();}
#define M 1000005
#define PII pair<int,int\>
#define PB push\_back
#define oo INT\_MAX
#define Set\_oo 0x3f
#define Is\_debug true
#define debug(...) if(Is\_debug)printf("DEBUG: "),printf(\_\_VA\_ARGS\_\_)
#define FOR(it,c) for(\_\_typeof((c).begin()) it=(c).begin();it!=(c).end();it++)
#define eps 1e-6
bool xdy(double x,double y){return x>y+eps;}
bool xddy(double x,double y){return x>y-eps;}
bool xcy(double x,double y){return x<y-eps;}
bool xcdy(double x,double y){return x<y+eps;}
int min3(int x,int y,int z){
int tmp=min(x,y);
return min(tmp,z);
}
int max3(int x,int y,int z){
int tmp=max(x,y);
return max(tmp,z);
}
int n;
int pgclear\[M\],plclear\[M\];
int main() {
ios\_base::sync\_with\_stdio(0);
while(~scanf("%d",&n)&&n){
Set(pgclear,0);
Set(plclear,0);
priority\_queue<int,vector<int\>,greater<int\> > pg;
priority\_queue<int,vector<int\>,less<int\> > pl;
Int ans=0;
for(int i=0;i<n;i++){
int tmp;
scanf("%d",&tmp);
for(int j=0;j<tmp;j++){
int tmp2;
scanf("%d",&tmp2);
pg.push(tmp2);
pl.push(tmp2);
}
for(;;){
if(pgclear\[pg.top()\]){
pgclear\[pg.top()\]--;
pg.pop();
}
else break;
}
for(;;){
if(plclear\[pl.top()\]){
pgclear\[pl.top()\]--;
pl.pop();
}else break;
}
int sg=pg.top();
int sl=pl.top();
pg.pop();pl.pop();
plclear\[sg\]++;
pgclear\[sl\]++;
ans+=sl-sg;
}
printf("%lld\\n",ans);
}
}