Compilare: user.cpp: In function ‘bool cmp(const std::pair<int, int>&, const std::pair<int, int>&)’: user.cpp:12:63: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = x.second, j = y.second; i < dp[x.first].size() and j < dp[y.first].size(); ++i, ++j) ^ user.cpp:12:90: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = x.second, j = y.second; i < dp[x.first].size() and j < dp[y.first].size(); ++i, ++j) ^ user.cpp: In function ‘int main()’: user.cpp:106:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (sta[i] == mov[i].size() or !oki[i]) ^ user.cpp:89:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("optic.in", "r", stdin); ^ user.cpp:90:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("optic.out", "w", stdout); ^ user.cpp:93:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:97:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); --x; --y; ^