Envío 6325

Código

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

int main() {
  int n; cin>>n;
  int arr[n];
  for(int i = 0; i < n; i++) {
    cin>>arr[i];
  }
  
  int leftSum = arr[0], rightSum = 0, k = 1;
  for(int j = 1; j < n; j++) {
    rightSum += arr[j];
  }
  bool rightOk = rightSum < 0, leftOk = leftSum > 0;
  while(k < n && (!rightOk || !leftOk)) {
    k++;
    leftSum += arr[k-1];
    rightSum -= arr[k-1];
    leftOk = leftSum > 0;
    rightOk = rightSum < 0;
  }

  if(rightOk && leftOk) {
    cout<<k<<endl;
  } else {
    cout<<"Impossible"<<endl;
  }
  return 0;
}