foo.cc: In function 'int main()':
foo.cc:48:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 scanf("%d%d", &n, &k);
 ~~~~~^~~~~~~~~~~~~~~~
foo.cc:49:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 for(i = 0;i < n;i ++) scanf("%d", a + i);
                       ~~~~~^~~~~~~~~~~~~

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