A21210.数字反转（升级版）

#include <bits/stdc++.h>
using namespace std;
string reverse(string s) {
	int zeroCount = 0;
	reverse(s.begin(), s.end());
	for (auto i : s)
		if (i == 48) {
			++zeroCount;
		} else {
			break;
		}
	s.erase(s.begin(),s.begin() + zeroCount);
	return (s != "" ? s : "0"); // 特判
}
string deleteTail(std::string s) {
	int zeroCount = 0;
	for (int i = s.size() - 1; i >= 0; --i) {
		if (s[i] == 48) {
			++zeroCount;
		} else {
			break;
		}
	}

	s.erase(s.end() - zeroCount, s.end());
	return (s != "" ? s : "0");
}

int main() {
	string s;
	cin >> s;
	if (s.back() == '%') {
		cout << reverse(s.substr(0, s.size() - 1)) << "%" << endl;
		return 0;
	}
	for (auto i : s) {
		string left, right;
		if (i == '/') {
			left = s.substr(0, s.find("/"));
			right = s.substr(s.find("/") + 1);
			cout << reverse(left) << "/" << reverse(right) << endl;
			return 0;
		}
		if (i == '.') {
			left = s.substr(0, s.find("."));
			right = s.substr(s.find(".") + 1);
			cout << reverse(left) << "." << deleteTail(reverse(right)) << endl;
			return 0;
		}
	}
	cout << reverse(s) << endl;
	return 0;
}