Serval and Parenthesis Sequence

https://codeforces.com/contest/1153/problem/C

题解：贪心+后缀和

/*
*@Author:   STZG
*@Language: C++
*/
#include <bits/stdc++.h>
#include<iostream>
#include<algorithm>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<string>
#include<vector>
#include<bitset>
#include<queue>
#include<deque>
#include<stack>
#include<cmath>
#include<list>
#include<map>
#include<set>
//#define DEBUG
#define RI register int
#define endl "\n"
using namespace std;
typedef long long ll;
//typedef __int128 lll;
const int N=300000+10;
const int M=100000+10;
const int MOD=1e9+7;
const double PI = acos(-1.0);
const double EXP = 1E-8;
const int INF = 0x3f3f3f3f;
int t,n,m,k,p,l,r,u,v;
int ans,cnt,flag,temp,sum;
int a[N];
char str[N];
struct node{};
int main()
{
#ifdef DEBUG
	freopen("input.in", "r", stdin);
	//freopen("output.out", "w", stdout);
#endif
    //ios::sync_with_stdio(false);
    //cin.tie(0);
    //cout.tie(0);
    //scanf("%d",&t);
    //while(t--){
    scanf("%d",&n);
    cin>>str;
    if(n%2){
        cout<<":("<<endl;
        return 0;
    }
    if(str[0]==')'||str[n-1]=='('){
        cout<<":("<<endl;
        return 0;
    }
    if(str[0]=='?')
        str[0]='(';
    if(str[n-1]=='?')
        str[n-1]=')';
    stack<char>st;
    for(int i=n-2;i>=1;i--){
        if(str[i]==')')
            cnt++;
        else if(str[i]=='('&&cnt>0)
            cnt--;
        a[i]=cnt;
    }
    for(int i=1;i<=n-2;i++){
        if(str[i]=='('){
            st.push(str[i]);
        }else if(str[i]==')'){
            if(st.size()==0){
                cout<<":("<<endl;
                return 0;
            }
            st.pop();
        }else{
            if(st.size()==0){
                str[i]='(';
                st.push('(');
            }else{
                if((int)st.size()<=a[i]){
                    str[i]='(';
                    st.push('(');
                }else{
                    str[i]=')';
                    st.pop();
                }
            }
        }
    }
    if(st.size()==0){
        cout<<str<<endl;
    }else{
        cout<<":("<<endl;
        return 0;
    }
    //}

#ifdef DEBUG
	printf("Time cost : %lf s\n",(double)clock()/CLOCKS_PER_SEC);
#endif
    //cout << "Hello world!" << endl;
    return 0;
}