Compilare: main.cpp: In function 'int main()': main.cpp:65:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < st.size() - 1; i++) { ~~^~~~~~~~~~~~~~~ main.cpp:33:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("domino.in", "r", stdin); ^ main.cpp:34:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("domino.out", "w", stdout); ^ main.cpp:37:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ main.cpp:39:27: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ^ main.cpp:57:13: warning: 'start' may be used uninitialized in this function [-Wmaybe-uninitialized] dfs(start); ^