foo.cc: In function 'int main()':
foo.cc:11:38: warning: 'len' may be used uninitialized in this function [-Wmaybe-uninitialized]
  s = 10 * (a[len - 2] - '0') + a[len - 1] - '0';
                                  ~~~~^~~

自豪的采用jd5进行评测(github.com/masnn/jd5)

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