foo.cc: In function 'int main()':
foo.cc:6:10: warning: unused variable 'i' [-Wunused-variable]
    6 |  int n,k,i,j,m;
      |          ^
foo.cc:6:12: warning: unused variable 'j' [-Wunused-variable]
    6 |  int n,k,i,j,m;
      |            ^
foo.cc:11:21: warning: 'k' may be used uninitialized in this function [-Wmaybe-uninitialized]
   11 |   for(int j=1;j<=n-i+k;j++)
      |                  ~~~^~

[Hydro](https://hydro.ac)提供评测服务