Compilare: user.cpp: In function ‘int main()’: user.cpp:115:17: warning: variable ‘edg1’ set but not used [-Wunused-but-set-variable] int edg1, edg2; ^ user.cpp:115:23: warning: variable ‘edg2’ set but not used [-Wunused-but-set-variable] int edg1, edg2; ^ user.cpp:133:45: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < edges[0][i].size(); j++) ^ user.cpp:134:53: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k = j + 1; k < edges[0][i].size(); k++) ^ user.cpp:138:45: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < edges[1][i].size(); j++) ^ user.cpp:139:53: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k = j + 1; k < edges[1][i].size(); k++) ^ user.cpp:100:43: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("entanglement.in", "r", stdin); ^ user.cpp:101:45: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("entanglement.out", "w", stdout); ^ user.cpp:104:39: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d", &op, &N, &M, &K); ^ user.cpp:113:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &a[i][j]); ^