Compilare: user.cpp: In function ‘int main()’: user.cpp:63:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < v[st[r]].size(); i++) ^ user.cpp:78:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < v[0].size(); i++) ^ user.cpp:17:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j, a, b, c, r; ^ user.cpp:18:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("maxflow.in", "r", stdin); ^ user.cpp:19:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("maxflow.out", "w", stdout); ^ user.cpp:20:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:23:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &a, &b, &c); ^