CodeVS 1045 回文数

题目大意：

http://codevs.cn/problem/1045/

代码：

#include <iostream>
#include <cstring>

using namespace std;

int n,m;
char ch[500];
int arr[500];
void print()
{
    for(int i = 0 ; i < 500; i++)
    {
        if(arr[i] != -1)
            cout << arr[i] << " " ;
        else
            break;
    }

    cout << endl;
}
void add()
{
    int tmp[500];
    int arr1[500];
    int count = 0;
    int l = 0;
    for(int i = 0; i < 500; i++)
    {
        if(arr[i] != -1)
            l++;
        else
            break;
    }
    l--;

    for(int i = l, j = 0; i >= 0 ;i--, j++)
    {
        arr1[j] = arr[i];
    }
    int flag = 0;
    while(l >= 0)
    {
        int t = (arr[l] + arr1[l] + flag) % n;
        flag = (arr[l] + arr1[l] + flag) / n;
        tmp[count++] = t;
        l--;

    }

    if(flag == 1)
        tmp[count++] = 1;

    for(int i = count - 1, j = 0; i >= 0; i--, j++)
    {
        arr[j] = tmp[i];
    }


}

bool judge()
{
    int l = 0;
    for(int i = 0; i < 500; i++)
    {
        if(arr[i] != -1)
            l++;
        else
            break;
    }

    l--;
    int s = 0;
    while(s <= l)
    {
        if(arr[s] == arr[l])
        {
            s++;
            l--;
        }
        else
            return false;
    }

    return true;
}


int main()
{
    cin >> n >> ch;

    for(int i = 0; i < 500; i++) arr[i] = -1;
    for(int i = 0; i < strlen(ch); i++)
    {
        int tmp = ch[i] - '0';
        if(tmp <= 9) arr[i] = tmp;
        else
            arr[i] = tmp - 7;
    }

    for(int i = 0; i <= 30; i++)
    {

        if(!judge())
        {
            add();

        }
        else
        {
            cout <<"STEP=" << i << endl;
            return 0;
        }

    }

    cout << "Impossible!" << endl;
    return 0;
}