C++双栈法实现字符串解码

string decodeString(string s) {
	string res = "";
	stackstrs;
	stacknums;
	int num = 0;
	int len = s.length();
	for (int i = 0; i < len; i++) {
		if (s[i] >= '0' && s[i] <= '9')num = num * 10 + s[i] - '0';
		else if ((s[i] >= 'a' && s[i] <= 'z') || (s[i] >= 'A' && s[i] <= 'Z'))res += s[i];
		else if (s[i] == '[') {
			nums.push(num);
			num = 0;
			strs.push(res);
			res = "";
		}
		else {
			int times = nums.top();
			nums.pop();
			for (int j = 0; j < times; j++)strs.top() += res;
			res = strs.top();
			strs.pop();
		}
	}
	return res;
}

int main() {
	string s = "3[a2[c]]";
	cout << decodeString(s);

	return 0;
}