Compilare: user.cpp: In function ‘int valid(std::vector<bool>)’: user.cpp:36:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < chk.size(); i++) ^ user.cpp:37:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = i+1; j < chk.size(); j++) ^ user.cpp:41:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k = 0; k < chk.size() && ok; k++) ^ user.cpp: In function ‘elem solve(int&)’: user.cpp:93:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < crt.size(); i++) ^ user.cpp:94:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = i+1; j < crt.size(); j++) ^ user.cpp: In function ‘int main()’: user.cpp:128:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("volei.in", "r", stdin); ^ user.cpp:129:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("volei.out", "w", stdout); ^ user.cpp:132:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &d); ^ user.cpp:135:45: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &pos[i].x, &pos[i].y); ^ user.cpp:136:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf(" %c", &c); ^ user.cpp: In function ‘elem solve(int&)’: user.cpp:16:8: warning: ‘x.elem::i’ may be used uninitialized in this function [-Wmaybe-uninitialized] struct elem ^ user.cpp:114:10: note: ‘x.elem::i’ was declared here elem x; ^ user.cpp:16:8: warning: ‘x.elem::j’ may be used uninitialized in this function [-Wmaybe-uninitialized] struct elem ^ user.cpp:114:10: note: ‘x.elem::j’ was declared here elem x; ^ user.cpp:16:8: warning: ‘x.elem::bef’ may be used uninitialized in this function [-Wmaybe-uninitialized] struct elem ^ user.cpp:114:10: note: ‘x.elem::bef’ was declared here