Compilare: user.cpp: In function ‘void solve(int, int, int)’: user.cpp:73:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < ans[nod].size(); ++i) { ~~^~~~~~~~~~~~~~~~~ user.cpp:90:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < ans[nod].size(); ++j) ~~^~~~~~~~~~~~~~~~~ user.cpp: In function ‘void getSol(int, int, int, int)’: user.cpp:118:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < ans[nod].size(); ++i) ~~^~~~~~~~~~~~~~~~~ user.cpp:120:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < ans[nod].size(); ++i) ~~^~~~~~~~~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:163:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (auto it = 0; it < ans.size(); ++it) { ~~~^~~~~~~~~~~~ user.cpp:143:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ro.in", "r", stdin); ^ user.cpp:144:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ro.out", "w", stdout); ^ user.cpp:148:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:150:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &cost[i]); ^ user.cpp:154:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^