hdu 4669——Mutiples on a circle

 

 

http://www.cnblogs.com/GBRgbr/archive/2013/08/14/3256584.html

參考之。

#include<iostream>#include<cstdio>#include<cstring>#include<algorithm>#include<cmath>#include<cstdlib>#include<map>#include<set>#include<string>#include<cctype>#include<vector>#include<queue>using namespace std;#define maxn 55000#define INF 10000000#define LL __int64int num[maxn];int len[maxn];int fac[maxn<<2];int dp[maxn][300];int n,k;void init(){fac[0]=1;for(int i=1;i<=n*3;i++)fac[i]=(fac[i-1]*10)%k;}int GetLen(int x){int len=0;while(x){len++;x/=10;}return len;}int main()  {  while(cin>>n>>k){init();for(int i=0;i<=n;i++)for(int j=0;j<=k;j++)dp[i][j]=0;for(int i=0;i<n;i++){scanf("%d",&num[i]);len[i]=GetLen(num[i]);}num[n]=num[0];len[n]=len[0];int sum=0;        int L=0;for(int i=n;i>0;i--)        {            sum=(num[i]*fac[L]+sum)%k;            dp[0][sum]++;            L+=len[i];        }      LL ans=dp[0][0];for(int i=1;i<n;i++){for(int j=0;j<k;j++)dp[i][(j*fac[len[i]]+num[i])%k]+=dp[i-1][j];sum=(sum*fac[len[i]]+num[i])%k;dp[i][num[i]%k]++;            dp[i][sum]--;            sum =((sum-num[i]*fac[L])%k+k)%k;            ans+=dp[i][0];}printf("%I64d\n",ans);}    return 0;  }