Compilare: user.cpp: In function ‘void preg(int, int)’: user.cpp:31:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < g[x].size(); ++i) ^ user.cpp: In function ‘void solve(int, int, std::vector<quest>)’: user.cpp:47:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < g[x].size(); ++i) ^ user.cpp:54:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (p1 != d1.size() || p2 != d2.size()) ^ user.cpp:54:45: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (p1 != d1.size() || p2 != d2.size()) ^ user.cpp:56:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (p1 == d1.size()) ^ user.cpp:58:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] else if (p2 == d2.size()) ^ user.cpp:68:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < d.size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:103:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("invtree.in", "r", stdin); ^ user.cpp:104:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("invtree.out", "w", stdout); ^ user.cpp:106:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &k); ^ user.cpp:109:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &x, &y, &l); aux.l = l; ^