The following code runs successfully on the USACO IDE, but it gives me a runtime error on codeforces with the exact same input and I have no idea why.
using namespace std;
int main(){
int n,t;
cin>>n>>t;
vector<int> arr(n+1);
for(int i=1;i<=n;i++) cin>>arr[i];
int a=1,b=1,mx=0;
long long s=0;
for(int i=1;i<=n;i++){
while(s+arr[b]<=t&&b<=n){
s+=arr[b];
b++;
}
mx=max(mx,b-a);
s-=arr[a];
a++;
}
cout<<mx;
}```