Compilare: user.cpp: In function ‘void df(int, int)’: user.cpp:33:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < A[x].size(); i++) { ^ user.cpp:45:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < B[x].size(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:73:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < e[0].size(); i++) { ^ user.cpp:85:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < e[1].size() && k1 < k; i++) { ^ user.cpp:106:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < e[1].size(); i++) { ^ user.cpp:111:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < e[0].size(); i++) { ^ user.cpp:60:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("karb.in", "r", stdin); ^ user.cpp:61:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("karb.out", "w", stdout); ^ user.cpp:63:34: 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:69:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &x, &y, &t); ^