Compilare: user.cpp: In function ‘bool check(int, int)’: user.cpp:24:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < s[b].size() && j < s[a].size()) { ^ user.cpp:24:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < s[b].size() && j < s[a].size()) { ^ user.cpp:30:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (j == s[a].size()) { ^ user.cpp: In function ‘int main()’: user.cpp:60:12: warning: suggest parentheses around assignment used as truth value [-Wparentheses] flag = j = 0; ^