Compilare: user.cpp: In function ‘void rezolva()’: user.cpp:117:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=1; j<val[i].size(); j++) ^ user.cpp:124:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0; j<val[i].size(); j++) ^ user.cpp:108:19: warning: unused variable ‘nr’ [-Wunused-variable] int i, j, k, nr=0; ^ user.cpp: In function ‘void solve()’: user.cpp:144:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("control.in", "r", stdin); ^ user.cpp:145:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("control.out", "w", stdout); ^ user.cpp:146:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n", &n); ^ user.cpp:150:19: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(lin); ^ /tmp/ccXeWHhj.o: In function `solve()': user.cpp:(.text+0x9ed): warning: the `gets' function is dangerous and should not be used.