hdu 1296 Polynomial Problem(多项式模拟)

Problem Description 
We have learned how to obtain the value of a polynomial when we were a middle school student. If f(x) is a polynomial of degree n, we can let.If we have x, we can get f(x) easily. But a computer can not understand the expression like above. So we had better make a program to obtain f(x).

Input 
There are multiple cases in this problem and ended by the EOF. In each case, there are two lines. One is an integer means x (0<=x<=10000), the other is an expression means f(x). All coefficients ai(0<=i<=n,1<=n<=10,-10000<=ai<=10000) are integers. A correct expression maybe likes  1003X^5+234X^4-12X^3-2X^2+987X-1000

Output 
For each test case, there is only one integer means the value of f(x).

Sample Input 
3 
1003X^5+234X^4-12X^3-2X^2+987X-1000

Sample Output 
264302

Notice that the writing habit of polynomial f(x) is usual such as 
X^6+2X^5+3X^4+4X^3+5X^2+6X+7 
-X^7-5X^6+3X^5-5X^4+20X^3+2X^2+3X+9 
X+1 
X^3+1 
X^3 
-X+1 etc. Any results of middle process are in the range from -1000000000 to 1000000000.

自己写的超丑，查了一年的bug,最后发现是多组数据而我只写了一组.........哭了

 #include <iostream>
 #include <cstdio>
 #include <string.h>
 #include <math.h>
 #include <algorithm>
 #define MIN(x,y) ((x)>(y))?(y):(x)
 #define MAX(x,y) ((x)>(y))?(x):(y)

 using namespace std;

 const int inf = 0x3f3f3f3f;
 const double dinf = 0xffffffff;
 const int vspot = ;
 const int espot = ;
 typedef long long ll;

 int bit[];
 int x, weishu, cnt;
 ll ans;
 int bound;
 bool e;
 bool positive;

 long long getNum()
 {
     if( !weishu )
     {
         if(positive)
             return ;
         else
             return -;
     }

     ll num = ;
     int k = weishu;
     for( int i = ; i < k; i++ )
     {
         weishu--;
         ll zhishu = ;
         for( int j = ; j < weishu; j++ )
             zhishu *= ;
         num += (long long)(bit[i]*zhishu);
     }

     if(positive)
         return num;
     else
         return -num;
 }

 bool check()
 {
     if ( cnt == bound )
         return true;
     return false;
 }

 int main()
 {

     while( cin >> x )
     {
         string ads, str = "+";
         cin >> ads;

         cnt = ;
         e = false;
         ans = ;

         if ( ads[]=='-' )
             str = ads;
         else
             str += ads;

         bound = str.size() - ;

         while(true)
         {
             ////////////////////符号部分////////////////////
             if ( str[cnt++]=='+' )
                 positive = true;
             else
                 positive = false;

         //////////////////////因数ai部分///////////////////
             weishu = ;
             memset( bit, -, sizeof(bit) );
             while(true)
             {
                 if ( str[cnt]>='' && str[cnt]<='' )
                 {
                     if ( check() )
                     {
                         e = true;
                         bit[weishu++] = str[cnt]-'';
                         ans += getNum();
                         break;
                     }
                     else
                         bit[weishu++] = str[cnt++]-'';
                 }
                 else
                     break;
             }
             if (e)
                 break;
         //////////////X^x部分//////////////////////
             ll ai = getNum();
             int cishu = ;
             if( check() )
                 e = true;
             else
             {
                 if ( str[cnt+] == '^' )
                 {
                     cnt++; cnt++;
                     if ( str[cnt]>='' && str[cnt]<='' )
                         cishu = str[cnt]-'';
                     else
                         { cishu = ; cnt++;}
                 }
             }
             if ( check() )
                 e = true;
             else
                 cnt++;
     //////////////计算部分/////////////////////////
             ll temp = ;
             for( int i = ; i < cishu; i++ )
                 temp *= x;
             ans += ai*temp;
             if (e)
                 break;
         }
         cout << ans << endl;
     }
     return ;
 }

再看看 别人写的.........我............我好菜呀QAQ

 #include<iostream>
 #include<cstdio>
 #include<cstring>
 #include<algorithm>
 using namespace std;
 int const nMax = ;
 #define sf scanf
 #define pf printf
 #define rep(i,n) for(int (i)=0;(i)<(n);(i)++)
 char s[nMax];
 int x;
 #define ll long long
 ll go(int &i)
 {
     int a,b,c;
     a = ;
     b = ;
     if(s[i] == '-') a*=-,i++;
     if(s[i] == '+') i++;
     while(s[i]>='' && s[i]<='')
     {
         b = b* + s[i]-'';
         i++;
     }
     if(b==) b = ;//这句就是应证X+1
     c = ;
     if(s[i] == 'X')
     {
         i++;
         if(s[i]=='^')
         {
             i++; c = ;
             while(s[i]>='' && s[i]<='')
             {
                 c = c* + s[i] - '';
                 i ++;
             }
         }
         else
         {
             c = ;
         }
     }
     ll ret = ;
     ret = (ll)a*b;
     for(int i=; i<c; i++) ret *= x;
     return ret;
 }
 int main()
 {
     while(cin >> x >> s)
     {
         int i = ;
         int l = strlen(s);
         ll ans = ;
         while(i<l)
         {
              ans += go(i);
         }
         cout << ans << endl;
     }
     return ;
 }