二十四点游戏

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


bool lessthan(char a, char b)
{
    if(b=='*' || b=='/' )
    {
        return true;
    }

    if(a=='+' || a=='-' )
    {
        return true;
    }
    return false;
}

void compute(stack<int> & s_num, char op)
{
    int b = s_num.top();
    s_num.pop();
    int a = s_num.top();
    s_num.pop();

    if(op=='*')
    {
        s_num.push(a*b);
    }
    else if(op=='/')
    {
        s_num.push(a/b);
    }
    else if(op=='+')
    {
        s_num.push(a+b);
    }
    else if(op=='-')
    {
        s_num.push(a-b);
    }
    else
    {
    }
}


int expression(char *str, int num)
{
    int res = 0;
    stack<int> s_num;
    stack<char> s_op;
    for(int i=0; i<num; i++)
    {
        if(str[i]>='0' && str[i]<='9')
        {
            int tmp = 0;
            int base = 1;
            tmp = base*(str[i]-'0');
            while(str[i+1]>='0' && str[i+1]<='9')
            {
                tmp = tmp*10 + (str[i+1]-'0');
                i++;
            }
            s_num.push(tmp);
        }

        else if(str[i] == '(')
        {
            s_op.push(str[i]);
        }
        else if(str[i] == '[')
        {
            s_op.push(str[i]);
        }
        else if(str[i] == '{')
        {
            s_op.push(str[i]);
        }

        else if(str[i] == ')')
        {
            char tmp = s_op.top();
            while(tmp!='(')
            {
                s_op.pop();
                //
                compute(s_num, tmp);

                tmp = s_op.top();
            }
            s_op.pop();
        }
        else if(str[i] == ']')
        {
            char tmp = s_op.top();
            while(tmp!='[')
            {
                s_op.pop();
                //
                compute(s_num, tmp);

                tmp = s_op.top();
            }
            s_op.pop();
        }
        else if(str[i] == '}')
        {
            char tmp = s_op.top();
            while(tmp!='{')
            {
                s_op.pop();
                //
                compute(s_num, tmp);

                tmp = s_op.top();
            }
            s_op.pop();
        }

        //*/+-
        else if( str[i]=='-' )
        {
            if( i==0 || str[i-1]=='(' ||str[i-1]=='{' ||str[i-1]=='[' ||str[i-1]=='+' ||str[i-1]=='-' ||str[i-1]=='*' ||str[i-1]=='/' )
            {
                i++;
                if(str[i]>='0' && str[i]<='9')
                {
                    int tmp = 0;
                    int base = 1;
                    tmp = base*(str[i]-'0');
                    while(str[i+1]>='0' && str[i+1]<='9')
                    {
                        tmp = tmp*10 + (str[i+1]-'0');
                        i++;
                    }
                    s_num.push(0-tmp);
                }
                else
                {
                    cout<<"error"<<endl;
                }
            }
            else
            {
                while(!s_op.empty())
                {
                    char tmp = s_op.top();
                    if( tmp!='(' && tmp!='[' && tmp!='{' && lessthan(str[i], tmp))
                    {
                        s_op.pop();
                        //
                        compute(s_num, tmp);
                    }
                    else
                    {
                        break;
                    }
                }

                s_op.push(str[i]);
            }
        }
        else if(str[i]=='*' || str[i]=='/' || str[i]=='+')
        {
            while(!s_op.empty())
            {
                char tmp = s_op.top();
                if( tmp!='(' && tmp!='[' && tmp!='{' && lessthan(str[i], tmp))
                {
                    s_op.pop();
                    //
                    compute(s_num, tmp);

                }
                else
                {
                    break;
                }
            }

            s_op.push(str[i]);
        }
        else
        {
        }

    }

    //final
    while(!s_op.empty())
    {
        char tmp = s_op.top();
        compute(s_num, tmp);
        s_op.pop();
    }

    return s_num.top();
}



void solve(int count, string *four, string *plusx, bool &flag)
{
    string fuhao[4] = {"+","-", "*", "/"};
    if(flag)
    {
        return;
    }
    else
    {
        if(count == 3)
        {
            string total;
            if(plusx[0]=="/" && plusx[1]=="*" && plusx[2]=="*")// /**
            {
                total = four[0]  + plusx[1] + four[2] + plusx[2] + four[3]+ plusx[0] + four[1];
            }
            else if(plusx[0]=="/" && plusx[1]=="*")
            {
                total = four[0]  + plusx[1] + four[2] + plusx[0] + four[1]+ plusx[2] + four[3];
            }
            else if(plusx[1]=="/" && plusx[2]=="*")
            {
                total = four[0]  + plusx[0] + four[1]+ plusx[2] + four[3]+ plusx[1] + four[2] ;
            }
            else
            {
                total = four[0]  + plusx[1] + four[1]+ plusx[2]+ four[2] + plusx[0]  + four[3];
            }

            char expr[100];

            int len = total.length();

            for(int i=0; i<len; i++)
            {
                expr[i] = total[i];
            }
            expr[len] = '\0';

            //cout<<expr<<"=";

            float tmp = expression(expr, len);
            //cout<<tmp<<endl;

            if(tmp - 24 < 0.001 && tmp - 24>-0.001)
            {
                flag = true;
            }
            else
            {
            }

        }
        else
        {
            for(int i=0; i<4; i++)
            {
                if(flag==false)
                {
                    plusx[count] = fuhao[i];
                    solve(count+1, four, plusx, flag);
                }
            }
        }
    }
    if(count==0 && flag==false)
    {
        cout<<"NONE";
    }
}

string trans(string str)
{
    if(str=="J")
    {
        str="11";
        return str;
    }
    else if(str=="Q")
    {
        str="12";
        return str;
    }
    else if(str=="K")
    {
        str="13";
        return str;
    }
    else if(str=="A")
    {
        str="1";
        return str;
    }
    else
    {
        return str;
    }
}

int main()
{
/*
    char str[100];
    cin.get(str, 100);
    int N = strlen(str);

    cout<<expression(str, N)<<endl;
    cout<<"true"<<endl;
*/
    string four[4];
    string tran[4];
    for(int i=0; i<4; i++)
    {
        cin>>four[i];
    }

    for(int i=0; i<4; i++)
    {
        if(four[i]=="joker" || four[i]=="JOKER")
        {
            cout<<"ERROR";
            return 0;
        }
        else
        {
            tran[i] = trans(four[i]);
        }
    }

    string plusx[3];
    bool flag = false;
    solve(0, tran, plusx, flag);

    if(flag)
        cout<<four[0]  + plusx[1] + four[1]+ plusx[2]+ four[2] + plusx[0]  + four[3];

    return 0;
}