ファーウェイ試験の難しい問題

#include<iostream>
#include<string>
using namespace std;
int compare(string &num1,string &num2);
string &add(string &num1,string &num2,string &result);
string &minu(string &num1,string &num2,string &result);
int main()
{  
	string num1,num2,result,temp;
	while(cin>>num1>>num2) {
		if(num1[0]=='-'&&num2[0]=='-') {
			num1.erase(0,1);
			num2.erase(0,1);
			result.push_back('-');
			add(num1,num2,result);
		}
		else if((num1[0]!='-'&&num2[0]=='-')||(num1[0]=='-'&&num2[0]!='-')) {
			if(num2[0]=='-')
				num2.erase(0,1);
			else
				num1.erase(0,1);
			int m=compare(num1,num2);
			if(m==0){
				result.push_back('-');
				minu(num2,num1,result);
			}
			else if(m==1)
				minu(num1,num2,result);
			else 
				result.push_back('0');
		}
		else
			add(num1,num2,result);
		cout<<result<<endl;
		result="";
	}
	return 0;	
}
int compare(string &num1,string &num2)                        //       
{
	if(num1.size()<num2.size())
		return 0;
	else if(num1.size()>num2.size())
		return 1;
	else
	{
		for(int i=0;i<num1.size();i++)
		{
			if(num1[i]<num2[i])
				return 0;
			else if(num1[i]>num2[i])
				return 1;
		}
		return 3;
	}
}
string &add(string &num1,string &num2,string &result)
{
	string temp;
	int m1=num1.size();
	int m2=num2.size();
	int m=m1>=m2?m2:m1;
	int flag=0,num;
	for(int i=0;i<m1&&i<m2;i++) {
		num=(num1[m1-1-i]-'0')+(num2[m2-1-i]-'0')+flag;
		if(num>=10) {
			flag=1;
			temp.push_back(num%10+'0');
		}
		else {
			temp.push_back(num+'0');
			flag=0;
		}
	}
	if(m1>m2) {
		for(int i=m1-1-m;i>=0;i--) {
			num=(num1[i]+'0')+flag;
			if(num>=10) {
				flag=1;
				temp.push_back(num%10+'0');
			}
			else {
				temp.push_back(num+'0');
				flag=0;
			}
		}
	}
	else if(m1==m2) {
		if(flag==1)
			temp.push_back('1');
	}
	else {
		for(int i=m2-1-m;i>=0;i--) {
			num=(num2[i]+'0')+flag;
			if(num>=10) {
				flag=1;
				temp.push_back(num%10+'0');
			}
			else {
				temp.push_back(num+'0');
				flag=0;
			}
		}
	}
	int n=temp.size();
	char c;
	for(int i=0;i<n/2;i++) {
		c=temp[i];
		temp[i]=temp[n-1-i];
		temp[n-1-i]=c;
	}
	result.append(temp);
	return result;
}
string &minu(string &num1,string &num2,string &result)       //num1         num2   ！
{
	string temp;
	int m1=num1.size();
	int m2=num2.size();
	int flag=0,num;
	for(int i=0;i<m2;i++)                                         //      
	{
		num=num1[m1-1-i]-num2[m2-1-i]-flag;
		if(num<0)
		{
			flag=1;
			temp.push_back(num+10+'0');
		}
		else
		{
			temp.push_back(num+'0');
			flag=0;
		}

	}
	if(m1>m2)
	{
		for(int i=m1-1-m2;i>=0;i--)
		{
			num=(num1[i]-'0')-flag;
			if(num<0)
			{
				temp.push_back(num+10+'0');
				flag=1;
			}
			else
			{
				temp.push_back(num+'0');
				flag=0;
			}
		}
	}
	int n=temp.size();
	char c;
	for(int i=0;i<n/2;i++)                      
	{
		c=temp[i];
		temp[i]=temp[n-1-i];
		temp[n-1-i]=c;
	}
	int pos=0;                                 //       0
	for(int i=0;i<n;i++)
	{
		if(temp[i]=='0')
			pos++;
		else
			break;
	}
	temp.erase(0,pos);
	result.append(temp);

	return result;
}

#include <iostream>
#include <map>
#include <string>
#include <ctype.h>
using namespace std;

int main()
{
	string str;
	while(cin>>str) {
		if(str.find(" ")!=-1)
		{
			cout<<"ERROR"<<endl;
			break;
		}
		if(str.length()>12&&str[str.find("Double")+6]=='D') {
			cout<<"ERROR"<<endl;
			break;
		}
		if(str.length()>6&&str.rfind("Double")==str.length()-6) {
			cout<<"ERROR"<<endl;
			break ;
		}
		for(int i=0;i<str.length();i++) {
			if(isdigit(str[i]))
			{
				cout<<"ERROR"<<endl;
				break;
			}
		}
		int flag=0;
		for(int i=0;i<str.length();) {
			if(str[i]=='O')
			{	
				if(flag==1)
					cout<<"1"<<"1"; 
				else cout<<"1";
				i=i+3;
			}
			else if(str[i]=='T'){
				if(str[i+1]=='h')
				{ 
					if(flag==1)
						cout<<"3"<<"3";
					else cout<<"3";
					i=i+5;
				}
				else {
					if(flag==1)
						cout<<"2"<<"2";
					else cout<<"2";
					i=i+3;
				}
			}
			else if(str[i]=='F') {
				if(str[i+1]=='o'){
					if(flag==1)
						cout<<"4"<<"4";
					else cout<<"4";
				}
				else {
					if(flag==1)
						cout<<"5"<<"5";
					else cout<<"5";
				}
				i=i+4;
			}
			else if(str[i]=='S') {
				if(str[i+1]=='i') {
					if(flag==1)
						cout<<"6"<<"6";
					else cout<<"6";
					i=i+3;
				}
				else {
					if(flag==1)
						cout<<"7"<<"7";
					else cout<<"7";
					i=i+5;
				}
			}
			else if(str[i]=='E') {
				cout<<"8";i=i+5;
			}
			else if(str[i]=='N') {
				if(flag==1)
					cout<<"9"<<"9";
				else cout<<"9";
				i=i+4;
			}
			else if(str[i]=='Z') {
				if(flag==1)
					cout<<"0"<<"0";
				else cout<<"0";
				i=i+4;
			}
			else if(str[i]=='D'){
				i=i+6;
				flag=1;
			}
		}
		cout<<endl;
	}
	return 0;
}

#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
using namespace std;
vector<char> arraylist;

bool isInRoom(vector<char> arraylist,char user)
{
	 bool temp=false;
	 for(int i=0;i<arraylist.size();i++) {
		 if(user==arraylist.at(i)) {
			 temp=true;
			 break;
		 }
	 }
	 return temp;
}

int main()
{
	int num;
	string users;
	cin>>num;
	cin>>users;

	int result=0;
	for(int i=0;i<users.length();i++) {
		if(isInRoom(arraylist,users[i]))
		{
			vector<char>::iterator iter = find(arraylist.begin(),arraylist.end(),users[i]);
			arraylist.erase(iter);
		}
		else if(arraylist.size()<num) {
			vector<char>::iterator iter = arraylist.end();
			arraylist.insert(iter,users[i]);
		}
		else {
			result++;
			continue;
		}
	}
	cout<<result/2<<endl;
	return 0;
}