在string长度增加的过程中，循环次数也变多，造成可能的死循环以及可能的（已经造成的）WA.求助QwQ

#include <iostream>
#include <string>
#include <algorithm>

#define DEBUG 0 //需要就打开，不需要不用管，监视变量用的

using namespace std;

string s;
int vis[107];

int main()
{
	cin >> s;

	for (int i = 0; i < s.size(); ++i)
	{
		if (s[i] == ')')
		{
			for (int j = i - 1; j >= 0; --j)
				if (s[j] == '(')
				{
					vis[i] = 1;
					vis[j] = 1;
					break;
				}
		}
		if (s[i] == ']')
		{
			for (int j = i - 1; j >= 0; --j)
				if (s[j] == '[')
				{
					vis[i] = 1;
					vis[j] = 1;
					break;
				}
		}
	}

	if (DEBUG)
	{
		cout << "Got string:";
		for (int i = 0; i < s.size(); ++i)
			cout << s[i] << " " << vis[i] << endl;
	}

	int n = s.size();

	for (int i = 0; i < s.size(); ++i)
		if (!vis[i])
		{
			if (s[i] == '(')
			{
				if (i != s.size() - 1) s.insert(s.begin() + i + 1, ')');
				else s.push_back(')');
				if (DEBUG) cout << s << endl;
			}
			if (s[i] == ')')
			{
				s.insert(s.begin() + i, '(');
				if (DEBUG) cout << s << endl;
			}
			if (s[i] == '[')
			{
				if (i != s.size() - 1) s.insert(s.begin() + i + 1, ']');
				else s.push_back(']');
				if (DEBUG) cout << s << endl;
			}
			if (s[i] == ']')
			{
				s.insert(s.begin() + i, '[');
				if (DEBUG) cout << s << endl;
			}
		}

	cout << s << endl;

	return 0;
}