Compilare: user.cpp: In function ‘int dfs(int, int, int, int)’: user.cpp:33:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < tail.size(); i++) candidates[stop + i] = tail[tail.size() - i - 1]; ^ user.cpp:34:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < head.size(); i++) candidates[start - i - 1] = head[i]; ^