guerra_por_territorio_roger_benet.java

import java.io.*;
public class solucao{
	public static void main(String[] args)throws IOException{
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter out = new BufferedWriter(new OutputStreamWriter(System.out));
        int[] vet = new int[110000];
		int i,n,sm1,sm2;
		String[] aux;
        n = Integer.parseInt(in.readLine());
        aux = in.readLine().split(" ");
		sm1 = 0;
		sm2 = 0;
		for(i = 0; i < n; i++){
			vet[i] = Integer.parseInt(aux[i]);
			sm1 += vet[i];
        }
		sm1 -= vet[i-1];
		sm2 += vet[i-1];
		for(i = n - 2; i > -1; i--){
			if(sm1 == sm2){
				out.write((i+1)+"\n");
				break;
			}
			else {
				sm1 -= vet[i];
				sm2 += vet[i];  
			}
		}
        out.flush();
    }
}