URAL 1057. Amount of Degrees(数位DP)

题目链接

我看错题了。。。都是泪啊，不存在3*4^2这种情况。。。系数必须为1。。。

 #include <cstdio>
 #include <cstring>
 #include <iostream>
 #include <vector>
 using namespace std;
 #define LL long long
 int num[];
 LL dp[][];
 int k,b;
 LL dfs(int pos,int pre,int bound)
 {
     int i,end;
     LL ans = ;
     if(pos == -)
     return pre == ;
     if(pre < )
     return ;
     if(!bound&&dp[pos][pre] != -)
     return dp[pos][pre];
     end = bound ? num[pos]:b-;
     for(i = ;i <= end;i ++)
     {
         if(i == )
         ans += dfs(pos-,pre,bound&&i == end);
         else if(i == )
         ans += dfs(pos-,pre-,bound&&i == end);
     }
     if(!bound)
     dp[pos][pre] = ans;
     return ans;
 }
 LL judge(LL x)
 {
     int pos = ;
     while(x)
     {
         num[pos++] = x%b;
         x /= b;
     }
     return dfs(pos-,k,);
 }
 int main()
 {
     LL x,y;
     memset(dp,-,sizeof(dp));
     cin>>x>>y>>k>>b;
     cout<<judge(y)-judge(x-)<<endl;
     return ;
 }