Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:15:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < l[x].size(); ++i) ^ user.cpp: In function ‘void dfs2(int)’: user.cpp:24:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < r[x].size(); ++i) ^ user.cpp: In function ‘void conex()’: user.cpp:40:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < CTC.size(); ++i) ^ user.cpp:41:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < CTC[i].size(); ++j) ^ user.cpp:47:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < r[i].size(); ++j) ^ user.cpp: In function ‘void dfsc(int, int)’: user.cpp:61:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < l[x].size(); ++i) ^ user.cpp: In function ‘bool match(int)’: user.cpp:70:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < bp[x].size(); ++i) ^ user.cpp:76:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < bp[x].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:86:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("plan.in", "r", stdin); ^ user.cpp:87:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("plan.out", "w", stdout); ^