POJ 2295 – A DP Problem

WA了N多次,猛然发现一处少写一符号,总算A掉了.这种题目就是要细心细心再细心.

#include <iostream>
#include<cstring>
#include<cmath>
using namespace std;
int main()
{
    char str[1000]={0};
    int i=0;
    int n=0;
    cin>>n;
    while (n–)
    {
        int len=0;
        cin>>str;
        len=strlen(str);
        int sign=1;
        int xx[2]={0};
        int cc[2]={0};
        int cnt=0;//
        int stack=0;
        int empty=1;
        for(i=0;i<len;i++)
        {
            switch (str[i])
            {
            case ‘=‘:
                if(!empty)
                {
                    cc[cnt]+=stack*sign;
                }
                empty=1;
                stack=0;
                cnt++;
                sign=1;
                break;
            case ‘-‘:
                if(!empty)
                {
                    cc[cnt]+=stack*sign;
                    stack=0;
                    empty=1;
                    sign=-1;
                }
                else
                    sign*=-1;

                break;
            case ‘+‘:
                if(!empty)
                {
                    cc[cnt]+=stack*sign;
                    stack=0;
                    sign=1;
                    empty=1;
                }
                break;
            case ‘x‘:
                if(!empty)
                {
                    xx[cnt]+=stack*sign;
                    stack=0;
                    empty=1;
                }
                else
                    xx[cnt]+=sign;
                sign=1;
                break;
            default:
                stack=stack*10+str[i]-‘0‘;
                empty=0;
                break;
            }
        }
        if(!empty)
        {
            cc[cnt]+=sign*stack;
        }
        if(xx[0]==xx[1])
        {
            if(cc[0]==cc[1])
            {
                cout<<“IDENTITY“<<endl;
            }
            else
                cout<<“IMPOSSIBLE“<<endl;
        }
        else 
        if((cc[1]-cc[0])%(xx[0]-xx[1])==0)
        {
            cout<<(cc[1]-cc[0])/(xx[0]-xx[1])<<endl;
        }
        else 
        {
            int flag1,flag2;
            if(cc[1]>cc[0])
                flag1=1;
            else 
                flag1=-1;
            if(xx[0]>xx[1])
                flag2=1;
            else flag2=-1;
            if(flag1*flag2>0)
                cout<<(cc[1]-cc[0])/(xx[0]-xx[1])<<endl;
            else
                cout<<(cc[1]-cc[0])/(xx[0]-xx[1])-1<<endl;
        }
    }
    return 0;
}