Gym 100418B : Sum of sequences

#include <iostream>
#include <cstring>
#include <cstdio>
#include <algorithm>
#include <cmath>
#include <vector>
#include <stack>
#include <map>
#include <set>
#include <queue>
#include <iomanip>
#include <string>
#include <ctime>
#include <list>
#include <bitset>
typedef unsigned char byte;
#define pb push_back
#define input_fast std::ios::sync_with_stdio(false);std::cin.tie(0)
#define local freopen("in.txt","r",stdin)
#define pi acos(-1)

using namespace std;
const int maxn = 1e5 + 500;
typedef struct data
{
  long long val;
  long long idxval;
  int idx;
  friend bool operator < (const data & x,const data & y)
  {
      return x.val < y.val;
  }
};
int LA,LB;
data A[maxn],B[maxn];
long long SB1,SB2,SB3;
long long QQ1,QQ2,QQ3;



int main(int argc,char *argv[])
{
  scanf("%d%d",&LA,&LB);
  for(int i = 0 ; i < LA; ++ i)
  {
      int x;
      scanf("%d",&x);
      A[i].val = x , A[i].idx = i , A[i].idxval = 1LL * i * x;
  }
  SB1 = SB2 = SB3 = QQ1 = QQ2 = QQ3 = 0; // HA HA HA HA 
  for(int i = 0 ; i < LB ; ++ i)
  {
      int x;
      scanf("%d",&x);
      B[i].val = x , B[i].idx = i , B[i].idxval = 1LL * i * x;
  }
  sort(A,A+LA);sort(B,B+LB);
  for(int i = 0 ; i < LB ; ++ i) QQ1 += B[i].idx , QQ2 += B[i].val , QQ3 += B[i].idxval;
  int ptr = 0;
  long long ans = 0;
  for(int i = 0 ; i < LA ; ++ i)
  {
        while(ptr < LB && B[ptr].val <= A[i].val) 
            {
                SB1 += B[ptr].idx;
                SB2 += B[ptr].val;
                SB3 += B[ptr].idxval;
                QQ1 -= B[ptr].idx;
                QQ2 -= B[ptr].val;
                QQ3 -= B[ptr].idxval;
                ptr++;
            }
        ans += 1LL*(A[i].idxval * ptr - A[i].val * SB1  - A[i].idx * SB2  + SB3);
        ans += 1LL*(A[i].idx * QQ2 - QQ3 - A[i].idxval * (LB-ptr) + A[i].val * QQ1);
  }
  printf("%I64d\n",ans);
  return 0;
}