我是这么写的
import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        while (in.hasNextInt()) {//注意while处理多个case
            int n = in.nextInt();
            int[] num=new int[n];
            int count=0;         
            for(int i=0;i<n;i++){
                num[i]=in.nextInt();              
            }
            int front=0;
            int end=n-1;
            while(front<end){
                int sum=num[end]-num[front];
                while(sum!=0&&end-front!=1){
                    if(sum>0){
                        sum=sum-num[++front];
                        count++;
                    }
                    else{
                        sum=sum+num[--end];
                        count++;
                    }
                }
                if(sum!=0&&end-front==1){
                	count++;
                }
                front++;
                end--;
                
            }
            System.out.println(count);
        }
    }
}