I have coded up the following solution to CSES’ Apple Division problem. When I individually run the test cases from CSES on my local compiler, I get the correct result. But, upon submitting the problem to the online grader, all I get for each test case is a 0. Not sure why this is happening.

Here’s my code:

#include <bits/stdc++.h>
using namespace std;
int n, arr[25];
vector<long long> weightSet;
long long ans = 1e7;
void perm(int idx) {
if(idx == n) {
bool setCheck[25]; memset(setCheck, -1, sizeof(setCheck));
long long setWeight = 0;
for(int i = 0; i < weightSet.size(); i++) {
setWeight+=arr[weightSet[i]];
setCheck[weightSet[i]] = 1;
}
long long remainingWeight = 0; for(int i = 0; i < n; i++) if(setCheck[i] != 1) remainingWeight+=arr[i];
ans = min(ans, llabs(setWeight - remainingWeight));
} else {
perm(idx+1);
weightSet.push_back(idx);
perm(idx+1);
weightSet.pop_back();
}
}
int main() {
cin >> n; for(int i = 0; i < n; i++) cin >> arr[i];
perm(0);
cout << ans << endl;
}

I’ve used simple recursion to generate subsets for each group, and for each subset I am storing the minimum difference value in the ans variable.

I am not sure what you mean by system test cases, but if you are referring to the test cases that show up after submission on CSES, then yes, I have locally ran them, and they are returning the correct output. However, I cannot say the same for CSES’ OJ, and I can’t seem to figure out why this is happening.

@Benq, yes apparently it’s happening in https://ide.usaco.guide/ too. I have downloaded all of CSES’ test cases and ran them on my system and this is the output I am getting on my console:

Each line is a the output for it’s respective test case on CSES. Could it be possible that the problem is caused by too much memory, since in each recursive step I am creating a new array?

The above output was generated using the following code:

#include <bits/stdc++.h>
using namespace std;
int n, arr[25];
vector<long long> weightSet;
long long ans = 1e10;
void perm(int idx) {
if(idx == n) {
bool weightSetCheck[25]; memset(weightSetCheck, 0, sizeof(weightSetCheck));
long long weightSetWeight = 0;
for(int i = 0; i < weightSet.size(); i++) {
weightSetWeight+=arr[weightSet[i]];
weightSetCheck[weightSet[i]] = 1;
}
long long remainingWeight = 0; for(int i = 0; i < n; i++) if(weightSetCheck[i] != 1) remainingWeight+=arr[i];
ans = min(ans, llabs(weightSetWeight - remainingWeight));
} else {
perm(idx+1);
weightSet.push_back(idx);
perm(idx+1);
weightSet.pop_back();
}
}
void solve() {
cin >> n; for(int i = 0; i < n; i++) cin >> arr[i];
perm(0);
weightSet.clear();
cout << ans << endl;
ans = 1e10;
}
int main() {
for(int i = 1; i<=17; i++) {
freopen((string("test_input ")+"("+to_string(i)+").txt").c_str(), "r", stdin);
solve();
}
}