# Editorial for Alohomora 2021 : Team Rocket

Problem Link: CodeChef: Practical coding for everyone
Author: @sharshach
Tester: @regex0754
Difficulty: Medium
PREREQUISTIES: Math, SegmentTree or related concepts

## Basic Idea :

Let us assume
SumRight=sum of all values whose X>currentX
SumTop=sum of all values whose Y>currentY

Now when we consider SumRight+sumTop we get the quadrant1 covered twice quadrant 2 and 4 covered once quadrant 3 covered 0 times.

Now reduce the totalSum (till now) you will get quadrant1 one time covered and quadrant3 subtracted once which is our goal

So our solution is sumLeft+sumTop-TotalSum

Now focus on calculating sumLeft

We can use segment tree for this focusing on 2 methods (updating the value) and getting sumRight.

Same way we can do for sumTop using y values in another segment tree

## Setter Code

``````#include<bits/stdc++.h>
using namespace std;

class Tree{
int N;
unordered_map <int,long long int> data;
long long int _getSumRight(int index){
if(index==0)return 0;
if(index%2==1){
return data[index]+(__builtin_popcount(index+1)==1?0:_getSumRight(index+1));
}
return _getSumRight(index/2);
}
int getNext2Power(int N){
if(__builtin_popcount(N)==1)return N;
int ans=1;
while(N){
N=N>>1;
ans=ans<<1;
}
return ans;
}
public:
Tree(int N){
this->N=getNext2Power(N);
}
void insert(int index,int value){
index+=N;
do{
if(data.find(index) == data.end()){
data[index]=value;
}
else{
data[index]+=value;
}
}while(index/=2);
}
long long int getSumRight(int index){
return _getSumRight(index+N);
}
};
class solve{
Tree *X,*Y;
long long int totalSum=0;
public:
solve(int N){
X=new Tree(N);
Y=new Tree(N);
}
void insert(int x,int y,int value){
X->insert(x+500000,value);
Y->insert(y+500000,value);
totalSum+=value;
}
long long int getSolution(int x,int y){
x+=500000;
y+=500000;
return X->getSumRight(x)+0ll+Y->getSumRight(y)-totalSum;
}
};
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
int t,n,x,y,v;
cin>>t;
while(t--){
cin>>n;
solve s(1000001);
while(n--){
cin>>x>>y>>v;
s.insert(x,y,v);
cout<<s.getSolution(x,y)<<endl;
}
}
return 0;
}
``````

## Tester Code

``````#include<bits/stdc++.h>
#define ll long long int
#define here cout<<"here\n"
#define pb push_back
#define mp make_pair
#define file freopen("input.txt","r",stdin); freopen("output.txt","w",stdout);
#define XLR8 ios_base::sync_with_stdio(false); cin.tie(NULL);
using namespace std;

const ll mod = 1e9+7;

const int MAX = 1000005;

vector<ll>arrx,arry,stx,sty;

ll query(ll si, ll ss, ll se,ll qs, ll qe, vector<ll>&st)
{

if( qs>se || qe<ss )
{
return 0;
}

if(ss>=qs && se<=qe)
{
return st[si];
}

ll mid = (ss+se)/2;
ll l = query(2*si, ss, mid, qs, qe,st);
ll r = query(2*si+1, mid+1, se, qs, qe,st);

return l+r;
}

void update(ll si, ll ss, ll se, ll qi, vector<ll>&arr, vector<ll>&st)
{
if(ss==se)
{
st[si] = arr[qi];
return;
}
ll mid = (ss+se)/2;
if(qi<=mid)
update(2*si,ss,mid,qi,arr,st);
else
update(2*si+1,mid+1,se,qi,arr,st);

st[si] = st[2*si] + st[2*si+1];
}

int main()
{

#ifndef ONLINE_JUDGE
file;
#endif

XLR8;

ll t;
cin>>t;
while(t--)
{
ll n;
cin>>n;
arrx.assign(MAX,0);
stx.assign(4*MAX,0);
arry.assign(MAX,0);
sty.assign(4*MAX,0);
ll i,j,k,l;
// here;
for(i=0;i<n;i++)
{
cin>>k>>j>>l;
k+=5e5;
j+=5e5;
arrx[k] += l;
arry[j] += l;

update(1,1,1e6,k,arrx,stx);
update(1,1,1e6,j,arry,sty);

cout<<query(1,1,1e6,j,1e6,sty)-query(1,1,1e6,1,k-1,stx)<<endl;
}
// here;

}

return 0;
}
``````