WX.cpp: In function 'V pro(V&, V&)':
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 'V exp(V&, long long int)':
WX.cpp:50:23: error: invalid initialization of non-const reference of type 'V& {aka std::vector<int>&}' from an rvalue of type 'V {aka std::vector<int>}'
return pro(exp(a, t-1), a);
^
WX.cpp:13:3: note: initializing argument 1 of 'V pro(V&, V&)'
V pro(V &a, V &b)
^
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]);
^