Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:18:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i < cx.size() - 1 && !ump[i + 1][j]) { ^ user.cpp:24:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(j < cy.size() - 1 && !ump[i][j + 1]) { ^ user.cpp: In function ‘int main()’: user.cpp:47:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < px.size(); i++) ^ user.cpp:50:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < py.size(); i++) ^ user.cpp:58:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < drept.size(); i++) { ^ user.cpp:60:99: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j = lower_bound(cx.begin(), cx.end(), drept[i].first.first) - cx.begin(); j < cx.size() && cx[j] < drept[i].second.first; j++) { ^ user.cpp:61:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k = st; k < cy.size() && cy[k] < drept[i].second.second; k++) { ^ user.cpp:66:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < cx.size(); i++) { ^ user.cpp:67:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j = 0; j < cy.size(); j++) { ^ user.cpp:31:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("colaj.in", "r", stdin); ^ user.cpp:32:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("colaj.out", "w", stdout); ^ user.cpp:33:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &N, &m, &p); ^ user.cpp:36:45: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d", &a, &b, &c, &d); ^