WX.cpp: In function 'V pro(const V&, const V&)':
WX.cpp:17:17: error: binding 'const int' to reference of type 'int&' discards qualifiers
for(int &x: a)
^
WX.cpp:18:21: error: binding 'const int' to reference of type 'int&' discards qualifiers
for(int &y: b)
^
WX.cpp:27:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i = 0; i<r.size(); i++)
^
WX.cpp: In function 'int main()':
WX.cpp:64:15: warning: unused variable 'j' [-Wunused-variable]
int k, i, j;
^
WX.cpp:66:34: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d%d%lld", &n, &k, &t);
^
WX.cpp:68:29: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d", &arr[i]);
^