24.cpp

24点游戏的源代码

#include <iostream>
#include <cmath>
#include <cstring>

using namespace std;
const double PE = 1e-6;
const int RESULT = 24;
const int COUNT = 4;

double number[COUNT];
string expression[COUNT];

bool Test(int n)
{
    if(n == 1)
    {
        if(fabs(RESULT - number[0]) < PE)
        {
            cout << expression[0] << endl;
            return true;
        }
        else
        return false;
    }

    for(int i = 0; i < n; i++)
    {
        for(int j = i+1; j < n; j++)
        {
            double a, b;
            string expa, expb;

            a = number[i];
            b = number[j];
            number[j] = number[n - 1];

            expa = expression[i];
            expb = expression[j];
            expression[j] = expression[n - 1];

            expression[i] = '('+expa+'+'+expb+')';
            number[i] = a + b;
            if(Test(n-1))
                return true;

            expression[i] = '('+expa+'-'+expb+')';
            number[i] = a - b;
            if(Test(n-1))
                return true;

            expression[i] = '('+expb+'-'+expa+')';
            number[i] = b - a;
            if(Test(n-1))
                return true;

            expression[i] = '('+expa+'*'+expb+')';
            number[i] = a * b;
            if(Test(n-1))
                return true;

            if(b>0.000001 || b<-0.000001)
            {
                expression[i] = '('+expa+'/'+expb+')';
                number[i] = a / b;
                if(Test(n-1))
                    return true;
            }

            if(a>0.000001 || a<-0.000001)
            {
                expression[i] = '('+expb+'/'+expa+')';
                number[i] = b / a;
                if(Test(n-1))
                    return true;
            }

            number[i] = a;
            number[j] = b;
            expression[i] = expa;
            expression[j] = expb;
        }
    }
    return false;
}

int main()
{
    cout << "Please enter " << COUNT << " numbers" << endl;
    for(int i = 0; i < COUNT; i++)
    {
        int x;
        char buffer[20];
        cin >> x;
        number[i] = x;
        itoa(x, buffer, 10);
        expression[i] = buffer;
    }
    if(Test(COUNT))
        cout << "Success!" << endl;
    else
        cout << "Fail!" << endl;
    system("pause");
    return 0;
}