Compilare: user.cpp: In function ‘void Backtracking(int)’: user.cpp:33:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (x == white.size()) { ^ user.cpp: In function ‘int main()’: user.cpp:52:21: warning: suggest parentheses around ‘+’ inside ‘>>’ [-Wparentheses] cin >> a[i] + 1; ^