Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:17:38: 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:26:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < bp[x].size(); ++i) ^ user.cpp:32:35: 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:60:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < ins.size(); ++i){ ^ user.cpp:69:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < ins.size(); ++i) ^ user.cpp:74:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < ins.size(); ++i) ^ user.cpp:80:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < cpls.size(); ++i) ^ user.cpp:81:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i < cpls.size() - 1) ^ user.cpp:85:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < ins.size(); ++i) ^ user.cpp:86:11: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if(!usedi[ins[i]]) ^ user.cpp:91:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < outs.size(); ++i) ^ user.cpp:92:11: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if(!usedo[outs[i]]) ^ user.cpp:99:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < mcs.size(); ++i) ^ user.cpp:42:35: 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:43:37: 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); ^ user.cpp:44:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m);