perm.cpp: In function 'int main()':
perm.cpp:47:27: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
47 | for (int i = 0; i < res.size(); i++) {
| ~~^~~~~~~~~~~~
perm.cpp:28:13: warning: unused variable 'cnt' [-Wunused-variable]
28 | int cnt = 0;
| ^~~
perm.cpp:29:13: warning: variable 'p' set but not used [-Wunused-but-set-variable]
29 | int p = 0;
| ^
perm.cpp:19:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
19 | freopen("input.txt", "r", stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
perm.cpp:20:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
20 | freopen("output.txt", "w", stdout);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/bin/ld: /tmp/cc1ELLuq.o: in function `main':
grader.cpp:(.text.startup+0x0): multiple definition of `main'; /tmp/ccuj6KCo.o:perm.cpp:(.text.startup+0x0): first defined here
/usr/bin/ld: /tmp/cc1ELLuq.o: in function `main':
grader.cpp:(.text.startup+0x240): undefined reference to `construct_permutation(long long)'
collect2: error: ld returned 1 exit status