各位计算机的高手们:
    你们好!
    在下最近碰到了一到很难的题(当然了，是相对于我这个小菜鸟而言 的),题目是这样的:
Sum

Mr. Jojer is given n numbers and an extra integer x, he wants to know whether there are two numbers whose sum is x. 


Input

The input file contains several test cases. The first line of each test case contains two integers, n(<=1000001) and x. From the next line of each test case, there are n numbers. 


Output

Each test case corresponds to a line in the output, which is either "YES" if there exists an answer or "NO" if not. 


Sample Input 


3 3
1 2 3
2 3
1 3




Sample Output 

YES
NO


题目来自于四川安心在线评判(网址:http://acm.scu.edu.cn/online_judge/problem.do?problem=1627),希望哪位好心人能帮帮我啊,在下不胜感激

• Re:一道让我痛不欲生的题目 (774) clean 2005-04-26 14:34:36
• Re:一道让我痛不欲生的题目 (800) frkstyc 2005-04-26 14:43:17
  • 排序后从两边向中间找 (2) xiaomi 2005-04-26 16:01:19
    • Re:排序后从两边向中间找 (69) frkstyc 2005-04-26 16:05:29
      • Re:排序后从两边向中间找 (8) uni 2005-04-26 20:30:50
        • Re:排序后从两边向中间找 (11) uni 2005-04-26 20:31:09
          • Re:排序后从两边向中间找 (56) frkstyc 2005-04-26 20:40:05
            • Re:排序后从两边向中间找 (44) uni 2005-04-26 21:08:05
              • Re:排序后从两边向中间找 (68) frkstyc 2005-04-26 21:17:14
                • Re:排序后从两边向中间找 (7) uni 2005-04-26 21:24:59
                  • Re:排序后从两边向中间找 (127) frkstyc 2005-04-26 21:27:47
                    • Re:排序后从两边向中间找 (32) uni 2005-04-26 21:30:20
                      • Re:排序后从两边向中间找 (50) frkstyc 2005-04-26 21:30:43
                        • Re:排序后从两边向中间找 (81) uni 2005-04-26 21:33:00