Compilare: main.cpp: In function 'bool ok(int, int)': main.cpp:18:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i < 0 || j < 0 || i >= n || j >= n) ~~^~~~ main.cpp:18:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i < 0 || j < 0 || i >= n || j >= n) ~~^~~~ main.cpp: In function 'bool ok2(int, int)': main.cpp:28:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i == 0 || j == 0 || i == n - 1 || j == n - 1) ~~^~~~~~~~ main.cpp:28:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i == 0 || j == 0 || i == n - 1 || j == n - 1) ~~^~~~~~~~ main.cpp: In function 'int main()': main.cpp:63:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < n; i++) ~~^~~ main.cpp:64:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < n; j++) ~~^~~ main.cpp:67:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < n; i++) ~~^~~ main.cpp:68:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < n; j++) ~~^~~ main.cpp:78:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(s > smax) ~~^~~~~~