Compilare: user.cpp: In function ‘bool pairup(int)’: user.cpp:19:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < A[x].size(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:76:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < ans.size(); i++) { ^ user.cpp:80:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < path.size(); i++) { ^ user.cpp:56:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("strazi.in", "r", stdin); ^ user.cpp:57:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("strazi.out", "w", stdout); ^ user.cpp:59:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ user.cpp:62:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ^