题解：

• 用大整数类BigInteger 不然会溢出

   

import java.math.BigInteger;
import java.util.Scanner;


public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n=sc.nextInt();
        BigInteger num1,num2,num3;
        for (int i = 1; i <=n ; i++) {
            num1=new BigInteger(sc.next());
            num2=new BigInteger(sc.next());
            num3=new BigInteger(sc.next());
            System.out.print("Case #"+i);
            if (num3.compareTo(num2.add(num1))>=0)
                System.out.println(": false");
            else
                System.out.println(": true");
        }
    }
}