Compilare: main.cpp: In function 'void solve()': main.cpp:14:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i <= n; i ++) ~~^~~~ main.cpp:17:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 2; i <= n; i ++) { ~~^~~~ main.cpp:26:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 1; j <= n; j++) ~~^~~~ main.cpp:32:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 1; j <= n; j++) ~~^~~~