C++ 解法, 执行用时: 38ms, 内存消耗: 452K, 提交时间: 2023-08-12 11:24:39

#include<bits/stdc++.h>

using namespace std;
#define clr(a,b)  memset(a,b,sizeof(a))

typedef long long ll;
const int maxnn = 10000 + 2;
const int minn = 100;
const double eps = 1e-6;
string toAns(ll n, int ne)
{
	if (n == 0)return "0";
	string str;
	while (n)
	{
		int tm = n % ne;
		if (tm <= 9) { str += '0' + tm; }
		else { str += 'A' + tm - 10; }
		n /= ne;
	}
	reverse(str.begin(), str.end());
	return str;
}

ll toTen(string str, int ne)
{
	ll ans = 0, arg = 1;
	for (int i = str.size() - 1; i >= 0; --i)
	{
		if (str[i] <= '9') { ans += (str[i] - '0')*arg; }
		else { ans += (str[i] - 'A' + 10)*arg; }
		arg *= ne;
	}
	return ans;
}
ll getOper(ll a, ll b, string op)
{
	if (op == "ADD") { return a + b; }
	else if (op == "SUB") { return a - b; }
	else if (op == "MUL") { return a * b; }
	else if (op == "DIV") { return a / b; }
	else { return a % b; }
}
int main()
{
	int  n;
	while (cin >> n)
	{
		ll ans = 0;
		int ne = 10;
		string str, old;
		while (n--)
		{
			cin >> str;
 			if (str == "CLEAR") { str.clear(); old.clear(); }
			else if (str == "EQUAL") { old.clear(); cout<< toAns(ans, ne) << endl; }
			else if (str == "CHANGE") { cin >> ne; }
			else if (str == "NUM"&&old.empty()) { cin >> str; ans = toTen(str, ne); }
			else if (str == "NUM" && !old.empty())
			{
				cin >> str; ans = getOper(ans, toTen(str, ne), old);
			}
			else   { old = str; }
		}
	}
	return 0;
}