Codeforces Round #209 (Div. 2)C

刷了一页的WA  。。终于发现了 哪里错了 快速幂模板里一个变量t居然开得long  ...

虽然代码写的丑了点 但是是对的 那个该死的long 啊..

 #include <iostream>
 #include<cstdio>
 #include<cstring>
 #include<algorithm>
 #include<stdlib.h>
 #include<vector>
 using namespace std;
 #define mod 1000000007
 #define LL __int64
 #define N 100010
 LL n,x,a[N],s,b[N];
 LL exp_mod(LL a,LL n,LL b)
 {
     long long t;
     if(n==) return %b;
     if(n==) return a%b;
     t=exp_mod(a,n/,b);
     t=t*t%b;
     if((n&)==) t=t*a%b;
     return t;
 }
 int main()
 {
     int i;
     cin>>n>>x;
     for(i = ; i <= n ; i++)
     {
         scanf("%I64d",&a[i]);
         s = s+a[i];
         b[i] = a[i];
     }
     for(i = ; i <= n ; i++)
     {
         b[i] = s-a[n-i+];
     }
     for(i = ; i <= n ;i++)
     a[i] = b[i];
     LL k = a[];
     int o = ;LL ss=a[];
     LL sum=;
     b[]-=a[];
     while()
     {
         if(b[o]==&&o<=n)
         {
             o++;
             b[o]-=a[o-];
             sum++;
             if(o>n) break;
             else
             continue;
         }
         if(o>n) break;
         if(sum%x!=) break;
         while(sum%x==&&o<=n)
         {
             sum/=x;
             ss++;
             b[o]--;
             if(b[o]==)
             {
                 o++;
                 b[o]-=a[o-];
                 sum++;
                 break;
             }
         }
         if(o>n) break;
     }
     while(sum&&sum%x==)
     {
         ss+=;
         sum/=x;
     }
     printf("%I64d\n",exp_mod(x,min(s,ss),mod));
     return ;
 }