Compilare: main.cpp: In function 'int main()': main.cpp:106:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<v.size();i++) ~^~~~~~~~~ main.cpp:117:15: warning: this 'if' clause does not guard... [-Wmisleading-indentation] if(valid[i][j]==0); ^~ main.cpp:118:17: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if' suma+=w[i][j]; ^~~~