C++：練習題

#include <iostream>
 
using namespace std;
 
int getNum(int n)
{
    if(n < 2)
    {
        return 0;
    }
 
    if(n == 2)
    {
        return 1;
    }
 
    return (n/3 + getNum(n%3 + n/3));
}
 
int main()
{
    int n;
    int num;
 
    while(cin >> n)
    {
        if(n >= 1 && n <= 100)
        {
            num = getNum(n);
            cout << num << endl;
        }
 
        if(n == 0)
        {
            break;
        }
    }
 
    return 0;
}

ctrl+d代表輸入結束： 

#include<iostream>

using namespace std;

int main()
{
    int n, m;
    while(cin >> n)
    {
        unsigned char arr[1000] = {0};
        while(n--)
        {
            cin >> m;
            if(m >= 1 && m <= 1000)
            {
                if(arr[m-1] == 0)
                {
                    arr[m-1] = 1;
                }
            }
        }
        
        for(int i = 0; i < 1000; i++)
        {
            if(arr[i] == 1)
            {
                cout << (i + 1) << endl;
            }
        }
    }
}

#include<iostream>
#include<string>

using namespace std;

int main()
{
    string num;
    while(getline(cin, num))
    {
        int size = num.size();
        int val = 0;
        int n = 0;
        bool flag = 0;

        for(int i = 0; i < size; i++)
        {
            if(num.at(i) >= 'a' && num.at(i) <= 'f')
            {
                flag = 1;
                n = num.at(i) - 'a' + 10;
            }
            else if(num.at(i) >= 'A' && num.at(i) <= 'F')
            {
                flag = 1;
                n = num.at(i) - 'A' + 10;
            }
            else if(num.at(i) >= '0' && num.at(i) <= '9')
            {
                flag = 1;
                n = num.at(i) - '0';
            }

            if(flag)
            {
                val = val * 16 + n;
            }
        }
        cout << val << endl;
    }
}

#include <iostream>
#include <vector>

using namespace std;

int main()
{
    int n;
    while(cin >> n)
    {
        if(n > 1000)
        {
            n = 1000;
        }

        vector<int> arr;
        for(int i = 0; i < n; i++)
        {
            arr.push_back(i);
        }
        int id = 0;
        while(arr.size() > 1)
        {
            for(int i = 0; i < arr.size(); i++, id++)
            {
                if(id == 2)
                {
                    arr.erase(arr.begin() + i);
                    id = 0;
                    if(i == (arr.size()))
                    {
                        break;
                    }
                }
            }
        }
        cout << arr[0] << endl;
    }

    return 0;
}

 

#include<iostream>
#include<string>

using namespace std;

int main()
{
    string s;
    char a;
    while(getline(cin, s))
    {
        for(int i = 1; i < s.size(); i++)
        {
            string str = s.substr(0, i);
        
    		if(str.find(s.at(i)) != string::npos)
            {      
                s.erase(i, 1);
		        i--;
            }
        }
        cout << s.c_str() << endl;
    }

    return 0;
}