bzoj 1026: [SCOI2009]windy数

D（不）P（会）类

#include<bits/stdc++.h>
#define N 200005
#define LL long long
#define inf 0x3f3f3f3f
#define ls tr[x][0]
#define rs tr[x][1]
using namespace std;
inline int ra()
{
    int x=0,f=1; char ch=getchar();
    while (ch<'0' || ch>'9') {if (ch=='-') f=-1; ch=getchar();}
    while (ch>='0' && ch<='9') {x=x*10+ch-'0'; ch=getchar();}
    return x*f;
}
int f[12][10];
int dp[12];
void init()
{
    memset(f,0,sizeof(f));
    for (int i=0; i<10; i++) f[1][i]=1;
    for (int i=2; i<=10; i++)
    {
        for (int j=0; j<10; j++)
        {
            for (int k=0; k<10; k++)
            {
                if (abs(j-k)>=2) 
                    f[i][j]+=f[i-1][k];
            }
        }
    }
}
int len;
int solve(int a)
{
    len=0;
    while (a)
    {
        dp[len++]=a%10;
        a/=10;
    } 
    int ans=0;
    for (int i=1; i<len; i++)
        for (int j=1; j<10; j++)
            ans+=f[i][j];
    for (int i=1; i<dp[len-1]; i++)
        ans+=f[len][i];
    for (int i=len-1; i>=1; i--)
    {
        for (int j=0; j<dp[i-1]; j++)
            if (abs(j-dp[i])>=2)
                ans+=f[i][j];
        if (abs(dp[i]-dp[i-1])<2) break;
    }
    return ans;
}
int main()
{
    init(); int a,b;
    while (~scanf("%d%d",&a,&b))
    {
        cout<<solve(b+1)-solve(a);
    }
    return 0;
}