Problem: https://codeforces.com/contest/862/problem/E.

My code follows the same logic as the official editorial and the USACO Guide solutions. I read all solutions and understood them before implementing it myself.

I tried printing out the values of variables, but everything seems good. However, the code gives the wrong output on the sample test case.

```
#include <bits/stdc++.h>
using namespace std;
#define int long long
const int MX = 1e18;
using vi = vector<int>;
#define F0R(i,n) for(int i=0;i<n;++i)
int32_t main()
{
int n, m, q;
cin >> n >> m >> q;
vi A(n), B(m);
auto sign_a = [&](int x){ return x%2==0?1:-1; };
auto sign_b = [&](int x){ return -sign_a(x); };
int Asum = 0;
F0R(i,n){
cin >> A[i];
Asum += sign_a(i)*A[i];
}
F0R(i,m) cin >> B[i];
vi Bsum(m); multiset<int> Bs;
F0R(i,n){
Bsum[0] += sign_b(i)*B[i];
}
Bs.insert(Bsum[0]);
F0R(j,m-n){
// Bsum[j] = sum of n length sliding window starting from B[j]
// -B[0] +B[1] -B[2] +B[3]...
// -B[1] +B[2] -B[3] +B[4]...
Bsum[j+1] = -(Bsum[j]+B[j]) + sign_b(n-1)*B[j+n];
Bs.insert(Bsum[j+1]);
}
int l, r, x;
auto ans = [&]() -> void{
// find minimum value of Asum + Bsum[j]
auto ub = Bs.upper_bound(-Asum);
int ret = MX;
if (ub != Bs.end()) ret = min(ret, abs(Asum+*ub));
if (ub != Bs.begin()) ret = min(ret, abs(Asum+*--ub));
cout << ret << '\n';
};
ans();
while(q--){
cin >> l >> r >> x;
l--, r--;
if ((r-l)%2==0){
Asum += sign_a(l)*A[l];
}
ans();
}
}
```

Can you please explain this? Thanks!