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OR4. S-expression

描述

S-expression is a prefix notation invented for and popularized by the programming language Lisp. Your task is to evaluate some simple S-expressions.
In this problem, S-expression is defined as:
1. An atom.
a. A nonnegative integer. Its value is the value of the integer.
b. A boolean value, true or false. Its value is the boolean value of itself.
c. A variable, consisting of no more than 10 lower case letters, excluding reserved words "if", "let", "true" and "false". Its value is the value bound to the variable. If the varible is not bound yet, produce an error "Unbound Identifier". (See below for details)
2. ( f x ... )
a. one of the following 4 forms: ( + x y ) ( - x y ) ( * x y ) ( / x y ) in which x and y are both S-expressions.
To evaluate the S-expression, you need to first evaluate x then evaluate y.
If the value of x or y is not an integer, produce an error "Type Mismatch".
If both x and y are integers, its value is the their sum(x+y)/difference(x-y)/product(x*y)/quotient(x/y). The division is the same as the integer division ("/" operator) in C/C++/Java/C#, truncated division. If the value of y is zero, produce an error: "Division By Zero".
b. ( if a b c ) in which a, b and c are S-expressions.
To evaluate the S-expression, you need to evaluate a at first.
If the value of a is not a boolean value, produce an error: "Type Mismatch".
If the value of a is true, evaluate b and the S-expression's value is the value of b.
If the value of a is false, evaluate c and the S-expression's value is the value of c.
Note that b or c may not be evaluated during the calculation.
c. ( let ( x a ) b ) in which x is a variable consisting of no more than 10 lower case letters, excluding reserved words "if", "let", "true" and "false", a and b are S-expressions.
To evaluate the S-expression, you need to first evaluate a.
Then bind the value of a to the variable x and evaluate b. Binding means if variable x appears in b, its value is the value of a. The S-expression's value is the value of b.
Note that if x is bound to another value in b, the outer binding is ineffective. For example the value of ( let ( x 1 ) ( let ( x 2 ) x ) ) is 2.
d. one of the following 3 forms: ( < x y ) ( > x y ) ( = x y ) in which x and y are S-expressions.
To evaluate the S-expression, you need to first evaluate x then evaluate y.
If the value of x or y is not an integer, produce an error "Type Mismatch".
If both x and y are integers, its value is a boolean value indicating whether x < y, x > y or x = y is true.
Given an S-expression, output its value. If an error occurs stop the evaluation and output the error.

输入描述

The first line contains an integer T (1 <= T <= 100), the number of testcases.
The following T lines each contain an S-expression consisting of no more than 200 characters.
It is guaranteed input S-expressions do not have any syntax error. The variables, parentheses, integers, true and false are seperated by at least one space.
For 100% of the data the integers in the whole evaluation will not exceed 32bit signed integers.

输出描述

For each testcase output the value of the S-expression or one of the three errors "Division By Zero", "Type Mismatch" and "Unbound Identifier" without quotes.

示例1

输入: 

2
( + ( - 3 2 ) ( * 4 5 ) ) 
( let ( x 4 ) ( if true x y ) )

输出: 

21
4

原站题解

C++ 解法, 执行用时: 1ms, 内存消耗: 364KB, 提交时间: 2017-07-01 

#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<algorithm>
#include<stack>
#include<sstream>
using namespace std;

struct s_expression{
	int kind; //kind=1:整数；kind=2：bool型；kind=3：异常
	int value; //(bool:false(1);true(2)) (异常：Unbound Identifier（1）；Type Mismatch（2）；Division By Zero（3）)
	s_expression(int cur_kind,int cur_value):kind(cur_kind),value(cur_value){}
	s_expression():kind(1),value(0){}
	void set(int cur_kind,int cur_value){kind=cur_kind,value=cur_value;}
};

map<string,s_expression> vari; 

void delete_part(stringstream &ss)
{
	string temp;
	ss>>temp;
	if(temp=="(")
	{
		int left=1,right=0;
		while(left>right)
		{
			string temp;
			ss>>temp;
			if(temp=="(") left++;
			else if(temp==")") right++;
		}
	}
}

s_expression singlepart(stringstream &ss)
{
	string temp;
	ss>>temp;
	if(temp!="("){
		if(temp>="0"&&temp<="9") return s_expression(1,stoi(temp));
		else if(temp=="true") return s_expression(2,2);
		else if(temp=="false") return s_expression(2,1);
		else {
			if(vari.find(temp)==vari.end())  return s_expression(3,1);   //Unbound Identifier
			else return vari[temp];
		}
	}
	else{
		ss>>temp;
		if(temp=="+"||temp=="-"||temp=="*"||temp=="/"||temp==">"||temp=="<"||temp=="=")
		{
			s_expression left=singlepart(ss),right=singlepart(ss),res;
			if(left.kind==2) res.set(3,2);  //Type Mismatch
			else if (left.kind==3) res=left;
			else if(right.kind==2) res.set(3,2);  //Type Mismatch
			else if (right.kind==3) res=right;
			else if(temp=="+") res.set(1,left.value+right.value);
			else if(temp=="-") res.set(1,left.value-right.value);
			else if(temp=="*") res.set(1,left.value*right.value);
			else if(temp=="/")
			{
				if(right.value==0) res.set(3,3); //Division By Zero
				else res.set(1,left.value/right.value);
			}
			else if(temp==">") res.set(2,(left.value>right.value)+1);
			else if(temp=="<") res.set(2,(left.value<right.value)+1);
			else res.set(2,(left.value==right.value)+1);
			ss>>temp;
			return res; 
		}
		else if(temp=="if")
		{
			s_expression res,a_temp=singlepart(ss);
			if(a_temp.kind==2&&a_temp.value==2){
				res=singlepart(ss);
				delete_part(ss);
			}
			else if(a_temp.kind==2&&a_temp.value==1){
				delete_part(ss);
				res=singlepart(ss);
			}
			else if(a_temp.kind==1) res.set(3,2);  //Type Mismatch
			else res=a_temp;
			ss>>temp;
			return res;
		}
		else
		{
			string temp1;
			s_expression res,last_value;
			ss>>temp;
 			ss>>temp1;
			bool flag=false;
			if(vari.find(temp1)!=vari.end())
			{
				flag=true;
				last_value=vari[temp1];
				vari.erase(temp1);
			}
			vari.insert(pair<string,s_expression>(temp1,singlepart(ss)));
			ss>>temp;
			res=singlepart(ss);
			vari.erase(temp1);
			if(flag!=false) vari.insert(pair<string,s_expression>(temp1,last_value));
			ss>>temp;
			return res;
		}
	}
}

int main()
{
	int sum;
	cin>>sum;
	cin.ignore(numeric_limits<streamsize>::max(),'\n'); 
	for(int z=0;z!=sum;z++)
	{
		vari.clear();
		stringstream ss;
		string input;
		getline(cin,input);
		ss<<input;
		s_expression flag=singlepart(ss);
		if(flag.kind==1) cout<<flag.value<<endl;
		else if(flag.kind==2&&flag.value==2) cout<<"true"<<endl;
		else if(flag.kind==2&&flag.value==1) cout<<"false"<<endl;
		else if(flag.kind==3&&flag.value==1) cout<<"Unbound Identifier"<<endl;
		else if(flag.kind==3&&flag.value==2) cout<<"Type Mismatch"<<endl;
		else cout<<"Division By Zero"<<endl;
	}
	return 0;
}

C++ 解法, 执行用时: 1ms, 内存消耗: 364KB, 提交时间: 2017-06-30 

#include<iostream>
#include<string>
#include<vector>
#include<stack>
using namespace std;
struct result {
	int error;//0 noerror 1 typemistach 2 nobound 3 divide error
	int type;//0 int 1 bool
	int val;
};
struct variable
{
	string name;
	int type;
	int val;
};
class solution {
public:
	result s_expressions(string& s,int& index, vector<variable> var) {
		if (index >= s.size()) return result();
		while (index<s.size()&&(s[index] == ' ' || s[index] == '(' || s[index] == ')')) ++index;
		if (s[index] == '+'|| s[index] == '-'|| s[index] == '*'|| s[index] == '/') {// + x y
			char p = s[index];
			++index;
			auto x = s_expressions(s, index,var);
			if (x.error != 0) return x;
			auto y = s_expressions(s, index,var);
			if (y.error != 0) return y;
			if (x.type == 1) {x.error = 1; return x;}
			if (y.type == 1) { y.error = 1; return y; }
			result res;
			res.error = 0;
			res.type = 0;
			if (p == '+') res.val = x.val + y.val;
			else if (p == '-') res.val = x.val - y.val;
			else if (p == '*') res.val = x.val * y.val;
			else {
				if (y.val == 0) {
					res.error = 3;
					return res;
				}
				res.val = x.val / y.val;
			}
			return res;
		}
		if (s[index] == '<' || s[index] == '>' || s[index] == '=') {
			char p = s[index];
			++index;
			auto x = s_expressions(s, index,var);
			if (x.error != 0) return x;
			if (x.type != 0) { x.error = 1; return x; }
			auto y = s_expressions(s, index,var);
			if (y.error != 0) return y;
			if (y.type != 0) { y.error = 1; return y; }
			result res; res.error = 0;
			res.type = 1;
			if (p == '<') res.val = (x.val < y.val);
			else if(p == '>') res.val = (x.val > y.val);
			else res.val = (x.val == y.val);
			return res;
		}
		if (s[index] <= '9'&&s[index] >= '0') {
			result res; res.error = 0; res.type = 0; res.val = 0;
			while (s[index] <= '9'&&s[index] >= '0') {
				res.val = res.val * 10 + s[index] - '0';
				++index;
			}
			return res;
		}
		if (s[index]>='a'&&s[index]<='z') {
			pair<int, string> str = dealwithString(s,index);
			result res;
			if (str.first == 0 || str.first == 1) {
				res.error = 0; res.type = 1;
				if (str.second == "true") res.val = 1;
				else res.val = 0;
				return res;
			}
			else if (str.first == 2) { //let
				pair<int, string> str = dealwithString(s, index);
				auto value = s_expressions(s,index,var);
				if (value.error != 0) return value;
				auto ptr = findvar(var, str.second);
				variable tmp; tmp.name = str.second; tmp.type = value.type; tmp.val = value.val;
				if (ptr == var.end()) var.push_back(tmp);
				else *ptr = tmp;
				return s_expressions(s,index,var);
			}
			else if (str.first == 3) { //if
				auto flag = s_expressions(s,index,var);
				if (flag.error != 0) return flag;
				if (flag.type == 0) { flag.error = 1; return flag; }
				result res; 
				if (flag.val) {
					res = s_expressions(s,index,var);
					nnoexec(s,index);
				}
				else {
					nnoexec(s, index);
					res = s_expressions(s, index,var);
				}
				return res;
			}
			else if (str.first == 4) { //var
				auto ptr = findvar(var,str.second);
				result res;
				if (ptr == var.end()) { res.error = 2; return res; }
				res.error = 0;
				res.type = ptr->type;
				res.val = ptr->val;
				return res;
			}
		}
        return result();
	}
	vector<variable>::iterator findvar(vector<variable>& var,const string& v) {
		auto ptr = var.begin();
		while (ptr!=var.end()) {
			if ((*ptr).name == v) return ptr;
			++ptr;
		}
		return var.end();
	}
	pair<int, string> dealwithString(string& s,int& index) {
		while (s[index] == ' ' || s[index] == '(' || s[index] == ')') ++index;
		int bec = index;
		while (s[index] <= 'z'&&s[index] >= 'a') ++index;
		string res = s.substr(bec,index-bec);
		if (res == "true") return make_pair(0,res);
		if(res=="false") return make_pair(1, res);
		if (res == "let") return make_pair(2,res);
		if (res == "if") return make_pair(3,res);
		return make_pair(4,res);
	}
	void nnoexec(string& s,int& index) {
		while (s[index] == ' ' || s[index] == ')') ++index;
		if (s[index] == '(') {
			stack<char> tmp;
			tmp.push('(');
			while (!tmp.empty()) {
				++index;
				if (s[index] == '(') tmp.push('(');
				else if (s[index] == ')') tmp.pop();
			}
			++index;
		}
		else {
			while ((s[index] <= '9'&&s[index] >= '0') || (s[index] <= 'z'&&s[index] >= 'a')) {
				++index;
				if (index == s.size()) break;
			}
		}
	}
};
int main() {
	int n = 0;
	char buf[210]; buf[0] = 0;
	cin >> n;
	getchar();
	while (n!=0) {
		cin.getline(buf, 210);
		string s(buf);
		solution sl;
		int index = 0;
		auto res = sl.s_expressions(s, index, vector<variable>());
		if (res.error == 0) {
			if (res.type == 0) cout << res.val << endl;
			else if (res.type == 1) {
				if (res.val == 1) cout << "true" << endl;
				else cout << "false" << endl;
			}
		}
		else if (res.error == 1) cout << "Type Mismatch" << endl;
		else if (res.error == 2) cout << "Unbound Identifier" << endl;
		else cout << "Division By Zero" << endl;
		--n;
	}
}

C++ 解法, 执行用时: 1ms, 内存消耗: 368KB, 提交时间: 2017-10-16 

#include <iostream>
#include <string>
#include <cstdio>
#include <sstream>
#include <cstdlib>
#include <map>

using namespace std;

static const string ERROR[] = {"Division By Zero", "Type Mismatch", "Unbound Identifier"};
map<string, string> variable;

bool is_atom(const string &exp)
{
	if(exp != "(" && exp != ")" && exp.find(' ') == string::npos) return true;
	else return false;
}

bool get_atom(const string &exp, string &sval)
{
	if(exp == "true" || exp == "false" || isdigit(exp[0])) sval = exp;
	else{
		map<string, string>::iterator iter = variable.find(exp);
		if(iter == variable.end())
		{
			cout<<ERROR[2]<<endl;
			return false;
		}else sval = iter->second;
	}
	return true;
}

void get_sub_exp(stringstream &sin, string &sub)
{
	int left_c = 0;
	string s;
	sub = "";
	do{
		sin>>s;
		if(s == "(") ++left_c;
		else if(s == ")") --left_c;
		sub += " " + s;
	}while(left_c != 0);
	sub = sub.substr(1);
}

bool eval(const string &exp, string &sval)
{
	if(is_atom(exp)) 
	{
		return get_atom(exp, sval);
	}else{
		stringstream sin(exp);
		string parenthsis, reversed;
		sin>>parenthsis>>reversed;

		string sub1, sub2, sval1, sval2;
		if(reversed == "let") 
		{
			string x;
			sin>>parenthsis>>x, get_sub_exp(sin, sub1), sin>>parenthsis;
			get_sub_exp(sin, sub2);
			if(eval(sub1, sval1))
			{
				variable[x] = sval1;
				if(eval(sub2, sval2))
				{
					sval = sval2;
					return true;
				}else
					return false;
			}else
				return false;
		}else if(reversed == "if")
		{
			string cond, sbool;
			get_sub_exp(sin, cond);
			get_sub_exp(sin, sub1);
			get_sub_exp(sin, sub2);
			if(eval(cond, sbool))
			{
				if(sbool == "true") return eval(sub1, sval);
				else if(sbool == "false") return eval(sub2, sval);
				else{
					cout<<ERROR[1]<<endl;
					return false;
				}
			}else
				return false;
		}else{
			char op = reversed[0];
			get_sub_exp(sin, sub1);
			get_sub_exp(sin, sub2);

			int val1, val2;
			if(eval(sub1, sval1) && eval(sub2, sval2))
			{
				if(isdigit(sval1[0]) && isdigit(sval2[0]))
				{
					val1 = atoi(sval1.c_str());
					val2 = atoi(sval2.c_str());
				}else{
					cout<<ERROR[1]<<endl;
					return false;
				}
			}else
				return false;

			char str[20];
			switch(op)
			{
				case '+':
					sprintf(str, "%d", val1+val2);
					sval = string(str);
					break;
				case '-':
					sprintf(str, "%d", val1-val2);
					sval = string(str);
					break;
				case '*':
					sprintf(str, "%d", val1*val2);
					sval = string(str);
					break;
				case '/':
					if(val2 == 0)
					{
						cout<<ERROR[0]<<endl;
						return false;
					}
					sprintf(str, "%d", val1/val2);
					sval = string(str);
					break;
				case '>':
					if(val1 > val2) sval = "true";
					else sval = "false";
					break;
				case '<':
					if(val1 < val2) sval = "true";
					else sval = "false";
					break;
				case '=':
					if(val1 == val2) sval = "true";
					else sval = "false";
					break;
			}
		} 
		sin>>parenthsis;
		return true;
	}
}

int main()
{
	int T;
	string s_exp;
	cin>>T, getline(cin, s_exp);
	while(T--)
	{
		getline(cin, s_exp);
		string sval;
		if(eval(s_exp, sval)) cout<<sval<<endl;		
	}
    return 0;
}

C++ 解法, 执行用时: 1ms, 内存消耗: 368KB, 提交时间: 2017-07-19 

#include <iostream>
#include <string>
#include <vector>
#include <utility>
#include <map>
  
using namespace std;
  
void goo() {
    string s;
    vector<string> stk;
    for(;;) {
        cin >> s;
        if(s=="(") stk.push_back(s);
        else if(s==")") {
            stk.pop_back();
            if(stk.empty()) return;
        } else if(stk.empty()) {
            if(s[0]>='0'&&s[0]<='9') {
                return ;
            } else if(s=="true" || s=="false") {
                return ;
            } else if(s!="if"&&s!="let") {
                return;
            }
        }
    }
    return ;
}
  
map<string,vector<pair<int,string> > > vars;
  
pair<int,string> go() {
    string s;
    vector<string> stk;
    pair<int,string> res;
    for(;;) {
        cin >> s;
        // cout <<"debug: " <<  s << endl;
        if(s=="(") stk.push_back(s);
        else if(s==")") {
            stk.pop_back();
            // cout << "rt: " << res.first << " " << res.second << endl;
            return res;
        } else {
            if(s[0]>='0'&&s[0]<='9') {
                return make_pair(atoi(s.c_str()),"N");
            } else if(s=="true" || s=="false") {
                return make_pair(0,"B"+s);
            } else if(s=="+") {
                pair<int,string> a,b;
                a = go(); if(a.second[0]=='E') return a;
                if(a.second[0]!='N') return make_pair(0,"EType Mismatch");
                b = go(); if(b.second[0]=='E') return b;
                if(b.second[0]!='N') return make_pair(0,"EType Mismatch");
                res = make_pair(a.first + b.first, "N");
            } else if(s=="-") {
                pair<int,string> a,b;
                a = go(); if(a.second[0]=='E') return a;
                if(a.second[0]!='N') return make_pair(0,"EType Mismatch");
                b = go(); if(b.second[0]=='E') return b;
                if(b.second[0]!='N') return make_pair(0,"EType Mismatch");
                res = make_pair(a.first - b.first, "N");
            } else if(s=="*") {
                pair<int,string> a,b;
                a = go(); if(a.second[0]=='E') return a;
                if(a.second[0]!='N') return make_pair(0,"EType Mismatch");
                b = go(); if(b.second[0]=='E') return b;
                if(b.second[0]!='N') return make_pair(0,"EType Mismatch");
                res = make_pair(a.first * b.first, "N");
            } else if(s=="/") {
                pair<int,string> a,b;
                a = go(); if(a.second[0]=='E') return a;
                if(a.second[0]!='N') return make_pair(0,"EType Mismatch");
                b = go(); if(b.second[0]=='E') return b;
                if(b.second[0]!='N') return make_pair(0,"EType Mismatch");
                if(b.first==0) return make_pair(0,"EDivision By Zero");
                res = make_pair(a.first / b.first, "N");
            } else if(s=="if") {
                pair<int,string> a,b,c;
                a = go(); if(a.second[0]=='E') return a;
                // cout << "ifa: " << a.first << " " << a.second << endl;
                if(a.second[0]!='B') return make_pair(0,"EType Mismatch");
                if(a.second[1]=='t') {
                    b = go(); if(b.second[0]=='E') return b;
                    // cout << "ifb: " << b.first << " " << b.second << endl;
                    goo();
                    res = b;
                } else {
                    goo();
                    b = go(); if(b.second[0]=='E') return b;
                    // cout << "ifc: " << b.first << " " << b.second << endl;
                    res = b;
                }
            } else if(s=="let") {
                string tmp; cin >> tmp; // (
                string var; cin >> var;
                pair<int,string> a,b;
                a = go(); if(a.second[0]=='E') return a;
                cin >> tmp; // )
                // cout << "let:" << var << "=" << a.first << " " << a.second << endl;
                  
                vars[var].push_back(a);
                b = go(); if(b.second[0]=='E') return b;
                vars[var].pop_back();
                res = b;
                  
            } else if(s=="<") {
                pair<int,string> a,b;
                a = go(); if(a.second[0]=='E') return a;
                if(a.second[0]!='N') return make_pair(0,"EType Mismatch");
                b = go(); if(b.second[0]=='E') return b;
                if(b.second[0]!='N') return make_pair(0,"EType Mismatch");
                if(a.first<b.first) res = make_pair(0,"Btrue");
                else res = make_pair(0,"Bfalse");
            } else if(s==">") {
                pair<int,string> a,b;
                a = go(); if(a.second[0]=='E') return a;
                if(a.second[0]!='N') return make_pair(0,"EType Mismatch");
                b = go(); if(b.second[0]=='E') return b;
                if(b.second[0]!='N') return make_pair(0,"EType Mismatch");
                if(a.first>b.first) res = make_pair(0,"Btrue");
                else res = make_pair(0,"Bfalse");
            } else if(s=="=") {
                pair<int,string> a,b;
                a = go(); if(a.second[0]=='E') return a;
                if(a.second[0]!='N') return make_pair(0,"EType Mismatch");
                b = go(); if(b.second[0]=='E') return b;
                if(b.second[0]!='N') return make_pair(0,"EType Mismatch");
                if(a.first==b.first) res = make_pair(0,"Btrue");
                else res = make_pair(0,"Bfalse");
            } else {
                if(vars[s].empty()) return make_pair(0,"EUnbound Identifier");
                return vars[s].back();
            }
        }
    }
    return make_pair(0,"Eerror");
}
  
void S_expressions() {
    pair<int,string> r = go();
      
    string s;
    if(r.second[0]=='E') getline(cin,s);
      
    if(r.second[0]!='N') cout << r.second.substr(1) << endl;
    else cout << r.first << endl;
}
  
int main() {
    ios::sync_with_stdio(false); cin.tie(0);
    int T;
    cin >> T;
    for(;T--;) {
        S_expressions();
    }
    return 0;
}

C++ 解法, 执行用时: 2ms, 内存消耗: 344KB, 提交时间: 2020-10-31 

#include <iostream>
#include <string>
#include <cstdio>
#include <sstream>
#include <cstdlib>
#include <map>

using namespace std;

static const string ERROR[] = {"Division By Zero", "Type Mismatch", "Unbound Identifier"};
map<string, string> variable;

bool is_atom(const string &exp)
{
	if(exp != "(" && exp != ")" && exp.find(' ') == string::npos) return true;
	else return false;
}

bool get_atom(const string &exp, string &sval)
{
	if(exp == "true" || exp == "false" || isdigit(exp[0])) sval = exp;
	else{
		map<string, string>::iterator iter = variable.find(exp);
		if(iter == variable.end())
		{
			cout<<ERROR[2]<<endl;
			return false;
		}else sval = iter->second;
	}
	return true;
}

void get_sub_exp(stringstream &sin, string &sub)
{
	int left_c = 0;
	string s;
	sub = "";
	do{
		sin>>s;
		if(s == "(") ++left_c;
		else if(s == ")") --left_c;
		sub += " " + s;
	}while(left_c != 0);
	sub = sub.substr(1);
}

bool eval(const string &exp, string &sval)
{
	if(is_atom(exp)) 
	{
		return get_atom(exp, sval);
	}else{
		stringstream sin(exp);
		string parenthsis, reversed;
		sin>>parenthsis>>reversed;

		string sub1, sub2, sval1, sval2;
		if(reversed == "let") 
		{
			string x;
			sin>>parenthsis>>x, get_sub_exp(sin, sub1), sin>>parenthsis;
			get_sub_exp(sin, sub2);
			if(eval(sub1, sval1))
			{
				variable[x] = sval1;
				if(eval(sub2, sval2))
				{
					sval = sval2;
					return true;
				}else
					return false;
			}else
				return false;
		}else if(reversed == "if")
		{
			string cond, sbool;
			get_sub_exp(sin, cond);
			get_sub_exp(sin, sub1);
			get_sub_exp(sin, sub2);
			if(eval(cond, sbool))
			{
				if(sbool == "true") return eval(sub1, sval);
				else if(sbool == "false") return eval(sub2, sval);
				else{
					cout<<ERROR[1]<<endl;
					return false;
				}
			}else
				return false;
		}else{
			char op = reversed[0];
			get_sub_exp(sin, sub1);
			get_sub_exp(sin, sub2);

			int val1, val2;
			if(eval(sub1, sval1) && eval(sub2, sval2))
			{
				if(isdigit(sval1[0]) && isdigit(sval2[0]))
				{
					val1 = atoi(sval1.c_str());
					val2 = atoi(sval2.c_str());
				}else{
					cout<<ERROR[1]<<endl;
					return false;
				}
			}else
				return false;

			char str[20];
			switch(op)
			{
				case '+':
					sprintf(str, "%d", val1+val2);
					sval = string(str);
					break;
				case '-':
					sprintf(str, "%d", val1-val2);
					sval = string(str);
					break;
				case '*':
					sprintf(str, "%d", val1*val2);
					sval = string(str);
					break;
				case '/':
					if(val2 == 0)
					{
						cout<<ERROR[0]<<endl;
						return false;
					}
					sprintf(str, "%d", val1/val2);
					sval = string(str);
					break;
				case '>':
					if(val1 > val2) sval = "true";
					else sval = "false";
					break;
				case '<':
					if(val1 < val2) sval = "true";
					else sval = "false";
					break;
				case '=':
					if(val1 == val2) sval = "true";
					else sval = "false";
					break;
			}
		} 
		sin>>parenthsis;
		return true;
	}
}

int main()
{
	int T;
	string s_exp;
	cin>>T, getline(cin, s_exp);
	while(T--)
	{
		getline(cin, s_exp);
		string sval;
		if(eval(s_exp, sval)) cout<<sval<<endl;		
	}
    return 0;
}

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