BZOJ1026: [Scoi2009]windy number

Description

Windy defines a windy number. A positive integer that does not contain a leading 0 and the difference of at least 2 of the adjacent two digits is called the windy number. Windy want to know,
What is the total number of windy between A and B, including A and b?

Input

Contains two integers, A B.

Output

An integer

Sample Input"Input Sample One"
1 10
"Input Sample Two"
theSample Output"Output Example One"
9
"Output Example II"
-HINT

"Data size and conventions"

100% of the data, meet 1 <= A <= B <= 2000000000

Topic Portal

Say Blog Park this link is a bit ugly ...

Change a new environment, learn something new--Digital DP

The first time to do this kind of problem is still very difficult to do,% of the puzzle bar, no problem can not live series

We set F[I][J] to represent the I-bit, the maximum number of J is the number of windy, then I can think of the equation: F[i][j]=sigma (f[i-1][k]) (ABS (K-J) >=2)

But we ask for a number ah, then we have to dismantle, open, for each one to record can

The code is as follows (feel the code speaks more clearly than I say):

#include <cstdio>#include<cstring>#include<cmath>#include<cstdlib>using namespacestd;intf[ -][ -],a[110000];typedefLong Longll;voiddp () { for(intI=0; i<=9; i++) f[1][i]=1;  for(intI=2; i<= A; i++)         for(intj=0; j<=9; j + +)             for(intk=0; k<=9; k++)                if(ABS (J-K) >=2) f[i][j]+=f[i-1][k];} ll Get_a (ll x) {ll len=0;  while(x) {a[++len]=x%Ten; X/=Ten; }    returnLen;} ll Findans (ll Len) {ll ans=0;  for(intI=1; i<len;i++)         for(intj=1; j<=9; j + +) ans+=F[i][j];  for(intI=1; i<a[len];i++) ans+=F[len][i];  for(inti=len-1; i>=1; i--)    {         for(intj=0; j<a[i];j++)        if(ABS (a[i+1]-J) >=2) ans+=F[i][j]; if(ABS (a[i+1]-a[i]) <2) Break; }    returnans;}intMain () {memset (F,0,sizeof(f)); intx, y; scanf ("%d%d",&x,&y); if(x>y) {inttt=x;x=y;y=tt;}    DP (); ll Lena=get_a (x), ansa=Findans (Lena); ll LenB=get_a (++y), ansb=Findans (LENB); printf ("%lld\n", ansb-ansa); return 0;}

By_lmy

BZOJ1026: [Scoi2009]windy number