Compilare: main.cpp: In function 'int main()': main.cpp:32:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<changes[v[i]].size()&&changes[v[i]][j]<i; j++) {} ~^~~~~~~~~~~~~~~~~~~~~ main.cpp:38:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(j!=changes[v[i]].size()-1&&changes[v[i]][j+1]==i) ~^~~~~~~~~~~~~~~~~~~~~~~~ main.cpp:40:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=j+1; k<changes[v[i]].size()&&changes[v[i]][k]<n; k++) ~^~~~~~~~~~~~~~~~~~~~~ main.cpp:10:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("blackwater.in","r",stdin); ^ main.cpp:11:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("blackwater.out","w",stdout); ^