Eroare de compilare: user.cpp:8:1: error: expected initializer before ‘stack’ stack <long long> st; ^ user.cpp: In function ‘int main()’: user.cpp:16:13: error: ‘st’ was not declared in this scope if (st.size() && s[st.top()]=='(' && s[i]==')') ^ user.cpp:17:13: error: ‘nxt’ was not declared in this scope nxt[st.top()]=i+1,st.pop(); ^ user.cpp:21:13: error: ‘nxt’ was not declared in this scope if (nxt[i]) ^