Luo Valley P2602 [ZJOI2010] digital count (the number of bits DP)

Topic links: https://www.luogu.com.cn/problem/P2602

 

This question is to the effect that a certain number of requirements within the interval 0-9 arise.

Statistics were counted number memory section 1 1, 2 1, 3 1 ......, there is a 2, 2 2, ......, a 1 9-9,2, ...... of the number of number, then the accumulated demand: * the number of times is accumulated.

Note that leading processing final frontier of 0 and DFS.

num: Which digital cnt: number of times now: the number of times that has occurred

recording a first dimension dp pos, recording a second dimension now, the third dimension record cnt, which kept ans.

 

AC Code:

 1 #include<cstdio>
 2 #include<iostream>
 3 #include<algorithm>
 4 #include<cstring>
 5 using namespace std;
 6 typedef long long ll;
 7 ll dp[20][20][20],ans[50];
 8 int a[50];
 9 ll DFS(int pos,int now,int limit,int lead,int cnt,int num){
10     if(pos==0) return now==cnt;//注意边界处理 
11     if(!limit&&!lead&&dp[pos][now][cnt]!=-1) return dp[pos][now][cnt];
12     int up=limit?a[pos]:9;
13     ll ans=0;
14     for(int i=0;i<=up;i++){
15         if(lead&&i==0) ans+=DFS(pos-1,now,limit&&i==a[pos],1,cnt,num);
16         else ans+=DFS(pos-1,now+(i==num),limit&&i==a[pos],0,cnt,num);
17     }
18     if(!lead&&!limit) dp[pos][now][cnt]=ans;
19     return ans;
20 }
21 void solve(ll x,int flag){
22     int len=0;
23     memset(dp,-1,sizeof(dp));
24     while(x){
25         a[++len]=x%10;
26         x/=10;
27     }
28     for(int I = 0 ; I <= . 9 ; I ++ ) {
 29          for ( int J = . 1 ; J <= len; J ++) { // the number of enumeration occurring 
30              IF (In Flag) ANS [I] + = J * the DFS (len, 0 , . 1 , . 1 , J, I);
 31 is              the else ANS [I] - = J * the DFS (len, 0 , . 1 , . 1 , J, I);
 32          }
 33 is      }
 34 is  }
 35  int main () {
 36      LL n-, m;
 37 [      Scanf ( " %% LLD LLD ",&n,&m);
38     solve(n-1,0); solve(m,1);
39     for(int i=0;i<=9;i++) printf("%lld ",ans[i]);
40     return 0;
41 }

AC Code