BZOJ 1799 - [AHOI2009]self 同类分布 - 枚举 数位DP

Description

找出$[L, R]$ 区间内有多少数， 各位数字和 能整除原数

Solution

枚举每个可能的数字和， 进行数位DP即可 ， 水爆

Code

 #include<cstdio>
 #include<cstring>
 #include<algorithm>
 #define ll long long
 using namespace std;

 int tot = ;
 int a[], mod;
 ll sum[][][];

 ll dfs(int pos, int ad, int r, bool lim, bool lead) {
     if(ad > mod)
         return ;
     if(!pos) return ad == mod && r == ;
     if(!lim && !lead && sum[pos][ad][r] != -)
         return sum[pos][ad][r];
     int up = lim ? a[pos] : ;
     ll tmp = ;
     for(int i = ; i <= up; ++i) {
         tmp += dfs(pos - , ad + i, (r *  + i) % mod, lim && a[pos] == i, lead && i == );
     }
     if(!lim && !lead)
         sum[pos][ad][r] = tmp;
     return tmp;
 }

 ll work(ll x) {
     int len = ;
     while(x) a[++len] = x % , x /= ;
     return dfs(len, , , true, true);
 }

 int main()
 {
     ll l, r;
     ll ans = ;
     scanf("%lld%lld", &l, &r);
     for(int i = ; i <= tot; ++i) {
         mod = i;
         memset(sum, -, sizeof(sum));
         ans += work(r) - work(l - );
     }
     printf("%lld\n", ans);
 }