P2657 [SCOI2009] windy 数

数位dp模板题

#include <bits/stdc++.h>
#define inf 2333333333333333
#define N 1000010
#define p(a) putchar(a)
#define For(i,a,b) for(int i=a;i<=b;++i)
//by war
//2020.7.12
using namespace std;
int l,r;
int f[20][20][3];
vector<int>dim;
void in(int &x){
    int y=1;char c=getchar();x=0;
    while(c<'0'||c>'9'){if(c=='-')y=-1;c=getchar();}
    while(c<='9'&&c>='0'){ x=(x<<1)+(x<<3)+c-'0';c=getchar();}
    x*=y;
}
void o(int x){
    if(x<0){p('-');x=-x;}
    if(x>9)o(x/10);
    p(x%10+'0');
}

int dfs(int x,int st,int op){
    if(!x) return 1;
    if(~f[x][st][op]) return f[x][st][op];
    int maxx=op?dim[x]:9,r=0;
    For(i,0,maxx){
        if(abs(st-i)<2) continue;
        if(st==11 && i==0) r+=dfs(x-1,11,op&(i==maxx));
        else r+=dfs(x-1,i,op&(i==maxx)); 
    }
    return f[x][st][op]=r;
}

int deal(int x){
    memset(f,-1,sizeof f);
    dim.clear();
    dim.push_back(2333);
    while(x){
        dim.push_back(x%10);
        x/=10;
    }
    return dfs(dim.size()-1,11,1);
}

signed main(){
    in(l);in(r);
    o(deal(r)-deal(l-1));
    return 0;
}