• [H] La La La - Sum

  • 时间限制: 1000 ms　内存限制: 65535 K
  • 问题描述

  • I have a integer m, and the other n numbers, can you find how many pairs of two integers in these n numbers that the sum of these two integers is equal to m?



  • 输入
  • Input until EOF.
    First line will contain two integers m (0<m<10000) and n (0<n<10000), and then n integers follow in next line. Each integer is x (0<x<10000).
  • 输出
  • Print the number of these pair of integers.
  • 样例输入
  • 100 5
1 2 50 98 99
  • 样例输出
  • 2
  • 提示
  • 无
  • 来源
  • Hungar
  • 操作

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