第二阶段

public static void main(String[] args) {
File f1 = new File("E:\\input.txt");
try {
BufferedReader br = new BufferedReader(new FileReader(f1));
}catch(FileNotFoundException e) {
e.printStackTrace();
}
Scanner sc = new Scanner(System.in);
System.out.println("请输入行数:");
int m = sc.nextInt();
System.out.println("请输入列数:");
int n = sc.nextInt();
System.out.println("请输入数组:");
int arr[][] = new int [n][m];
for(int i=0;i<n;i++)
for(int j=0;j<m;j++) {
arr[i][j] = sc.nextInt();
}
int sum = 0;
for(int i=0;i<n;i++) {
for(int j=0;j<m;j++) {
if(arr[i][j]<0)
sum=sum;
else{
sum=sum+arr[i][j];
}
}

}
System.out.println("最大子数组之和为:" + sum);

}