Compilare: user.cpp: In function ‘void solve()’: user.cpp:59:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < color[i].size(); j++){ ^ user.cpp:83:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(nr == s.size()) ^ user.cpp: In function ‘int main()’: user.cpp:89:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("unlock.in", "r", stdin); ^ user.cpp:90:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("unlock.out", "w", stdout); ^ user.cpp:91:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &t); ^ user.cpp:93:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &n, &m, &k); ^ user.cpp:96:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &a[i][j]); ^