Compilare: user.cpp: In function ‘void Expand()’: user.cpp:21:57: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (xidx[level] = 0; xidx[level] < vec[x[level]].size(); xidx[level]++) { ^ user.cpp:25:58: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (yidx[level] = 0; yidx[level] < vec[y[level]].size(); yidx[level]++) { ^ user.cpp: In function ‘int main()’: user.cpp:54:57: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (center2_idx = 0; center2_idx < vec[center1].size(); center2_idx++) { ^ user.cpp:72:57: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (centera_idx = 0; centera_idx < vec[center1].size(); centera_idx++) { ^ user.cpp:74:72: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (centerb_idx = centera_idx + 1; centerb_idx < vec[center1].size(); centerb_idx++) { ^ user.cpp:39:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbpal.in", "r", stdin); ^ user.cpp:40:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); ^ user.cpp:42:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &i, &j); ^ user.cpp:48:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf(" %c", &(ch[i])); ^ user.cpp:89:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbpal.out", "w", stdout); ^