Compilare: main.cpp: In function 'int main()': main.cpp:23:9: warning: unused variable 'x' [-Wunused-variable] int n,i,x,ans=0; ^ main.cpp:21:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("purification.in","r",stdin); ^ main.cpp:22:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("purification.out","w",stdout); ^ main.cpp:24:15: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ main.cpp:26:75: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&v[i]),t[i]=i,cnt[i]=1,from[i]=i,s.insert({i,v[i],1}),ans+=v[i]; ^ main.cpp:28:29: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&nex[i]),nex[i]++; ^