Compilare: main.cpp: In function 'int dfs(int, int)': main.cpp:38:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (; ptr[x] < lda[x].size(); ++ptr[x]) { ~~~~~~~^~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:66:35: 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); ^ main.cpp:67:37: 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); ^ main.cpp:68:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] for(scanf("%d %d", &n, &m); m; --m) { ^ main.cpp:69:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &x, &y, &z); ^