tjut 4869

来源：互联网发布：c语言算法是什么编辑：程序博客网时间：2024/06/16 21:39
#include <iostream>  #include <cstdio>  #include <cstring>  #include <ctime>  #include <algorithm>  #include <cmath>  #include <queue>  #include <vector>  using namespace std;    #define LL __int64  const int maxn=1e5+10;  const int mod=1e9+9;  LL c[maxn];  LL pow_mod(LL a,int b)  {      LL s=1;      while(b)      {          if(b&1)s=s*a%mod;          a=a*a%mod;          b=b>>1;      }      return s;  }  int main()  {      int n,m;      //freopen("C:\\Documents and Settings\\Administrator\\桌面\\in.txt","r",stdin);      //freopen("C:\\Documents and Settings\\Administrator\\桌面\\out.txt","w",stdout);      //printf("%I64d\n",pow_mod(2,10));      while(scanf("%d%d",&n,&m)!=EOF)      {          int i,j,k,x,p,q;          i=j=0;          for(k=0;k<n;k++)          {              scanf("%d",&x);              //求最小1的个数i              if(i>=x)p=i-x;              else if(j>=x)p=((i&1)==(x&1)?0:1);              else p=x-j;              //求最大1的个数j              if(j+x<=m)q=j+x;              else if(i+x<=m)q=(((i+x)&1)==(m&1)?m:m-1);              else q=2*m-(i+x);              i=p;j=q;              //printf("**%d %d\n",i,j);          }            LL ans=0;          c[0]=1;          if(i==0)ans+=c[0];          for(k=1;k<=j;k++)          {              if(m-k<k)c[k]=c[m-k];              else c[k]=c[k-1]*(m-k+1)%mod*pow_mod(k,mod-2)%mod;              if(k>=i&&(k&1)==(i&1))ans+=c[k];          }          printf("%I64d\n",ans%mod);      }      return 0;  }
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