Hd1001

Posted 2023-03-01 xihuangwutong

#include <stdio.h>
int main()

      int m;
      int n;
      while (scanf("%d",&n)!=EOF)
      
            if (n%2==0)
                  m=n/2*(n+1);
            else
                  m = (n+1)/2*n;
            printf("%d\\n\\n", m);
      
      return 0;

For each case, output SUM(n) in one line, followed by a blank line. You may assume the result will be in the range of 32-bit signed integer.

这一句说明结果是32位整形以内

使用n*(n+1)/2的时候，n*(n+1)可能会超过32位整形，所以要先执行除以2的动作
保证不会造成内存溢出