Compilare: main.cpp: In function 'int solve(int*)': main.cpp:38:51: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=lst;j<=i && st[cnt].size() <= k;j++){ ~~~~~~~~~~~~~~~^~~~ main.cpp:39:58: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j2=2;j2<=l[j] && st[cnt].size() <= k;j2++){ ~~~~~~~~~~~~~~~^~~~ main.cpp:46:51: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=i;j>=lst && dr[cnt].size() <= k;j--){ ~~~~~~~~~~~~~~~^~~~ main.cpp:47:58: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j2=2;j2<=l[j] && dr[cnt].size() <= k;j2++){ ~~~~~~~~~~~~~~~^~~~ main.cpp:65:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int a=0;a<dr[i-1].size() && a <= fre[i] && j + a <= k;a++) ~^~~~~~~~~~~~~~~ main.cpp:66:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int b=0;b<st[i].size() && a + b <= fre[i] && j + a + b <= k;b++){ ~^~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:77:51: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("nave_interdimensionale.in","r",stdin); ^ main.cpp:78:53: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("nave_interdimensionale.out","w",stdout); ^