OJ刷题记录：问题 B: 简单正则

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

using namespace std;

string str;
int LEN, pos;

int fun() {
	int son = 0, res = 0;
	
	while (pos < LEN) {
		if (str[pos] == '(') {
			pos++;
			son += fun();
		} else if (str[pos] == '|') {
			pos++;
			res = max(son, res);
			son = 0;
		} else if (str[pos] == ')') {
			pos++;
			break;
		} else {
			pos++;
			son++;
		}
	}
	res = max(son, res);
	
	return res;
}

int main() {
	cin >> str;
	
	LEN = str.size();
	pos = 0;
	
	cout << fun();
	
	return 0;
}