Lưu ý: Các code mẫu dưới đây chỉ mang tính tham khảo và có thể không AC được bài tập này

Code mẫu của ladpro98

#include <cstring>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <climits>
#include <cstdlib>
#include <ctime>
#include <memory.h>
#include <cassert>
#define FOR(i, a, b) for(int i = (a); i < (b); i++)
#define REP(i, a, b) for(int i = (a); i <=(b); i++)
#define FORD(i, a, b) for(int i = (a); i > (b); i--)
#define REPD(i, a, b) for(int i = (a); i >=(b); i--)
#define TR(it, a) for(typeof((a).begin()) it = (a).begin(); it != (a).end(); ++it)
#define SZ(a) (int((a).size()))
#define ALL(a) (a).begin(), (a).end()
#define PB push_back
#define MP make_pair
#define LL long long
#define LD long double
#define II pair<int, int>
#define X first
#define Y second
#define VI vector<int>

const int N = 20;
using namespace std;
typedef unsigned LL i64;

i64 POW[N], F[N][N * 9], a, b, A, B;
bool was[N][N * 9];
int ntest;

i64 DP(int i, i64 n, int sum) {
    i64 l = n * POW[i], r = (n + 1) * POW[i] - 1;
    if (r < A || B < l) return 0;
    if (i == 0) return n && sum == 0;
    if (A <= l && r <= B && was[i][sum]) return F[i][sum];
    i64 ans = 0;
    REP(j, 0, 9) if (sum >= j) ans += DP(i - 1, n * 10 + j, sum - j);
    if (A <= l && r <= B) was[i][sum] = 1, F[i][sum] = ans;
    return ans;
}

int main() {
    POW[0] = 1;
    FOR(i, 1, N) POW[i] = POW[i - 1] * 10;
    cin >> ntest;
    while (ntest--) {
        cin >> a >> b;
        i64 res = 0;
        FOR(sum, 1, 172) {
            A = (a % sum == 0) ? (a / sum) : (a / sum + 1);
            B = b / sum;
            res += DP(19, 0, sum);
        }
        cout << res << '\n';
    }
    return 0;
}

Code mẫu của RR

#include <iostream>
#include <algorithm>
#include <cstring>

#define FOR(i,a,b) for(int i=(a), _b=(b); i<=_b; i++)
#define FORD(i,a,b) for(int i=a; i>=b; i--)
#define REP(i,a) for(int i=0; i<a; i++)
#define ll long long
using namespace std;

int a[20], now;
ll f[20][200][2];
int memo[20][200][2];

void init(ll gh) {
    ll save = gh;
    memset(a, 0, sizeof a);
    if (!gh) a[0] = 1;
    while (gh) {
        a[0]++;
        gh /= 10;
    }
    gh = save;
    int now = a[0];
    while (gh) {
        a[now--] = gh%10;
        gh /= 10;
    }
}

ll dp(int i, int sum, bool lower) {
    if (memo[i][sum][lower] == now) return f[i][sum][lower];
    memo[i][sum][lower] = now;

    if (i == a[0]) {
        if (sum > 9 || (!lower && sum > a[i])) return f[i][sum][lower] = 0LL;
        else return f[i][sum][lower] = 1LL;
    }

    f[i][sum][lower] = 0LL;
    FOR(now, 0, min(lower?9:a[i],sum)) {
        f[i][sum][lower] += dp(i+1, sum - now, lower || (now < a[i]));
    }
    return f[i][sum][lower];
}

ll get(ll gh) {
    ll res = 0;
    FOR(sum, 1, min(gh,145LL)) {
        now ++;
        init(gh / sum);
        res += dp(1, sum, false);
    }

    return res;
}

int main() {
    int test;
    scanf("%d", &test);
    while (test--) {
        ll a, b;
        scanf("%lld %lld", &a, &b);
        printf("%lld\n", get(b) - get(a-1));
    }
    return 0;
}

Code mẫu của hieult

#pragma comment(linker, "/STACK:16777216")

#include<cstdio>
#include<cmath>
#include<cstring>
#include<cstdlib>
#include<cassert>
#include<ctime>
#include<algorithm>
#include<iterator>
#include<iostream>
#include<cctype>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<queue>
#include<list>
//#include<conio.h>
#define ep 0.000000001
#define maxn 10011
#define oo 1111111111
#define modunlo 111539786
#define TR(c, it) for(typeof((c).begin()) it=(c).begin(); it!=(c).end(); it++)
#define ull unsigned long long

double const PI=4*atan(1);

using namespace std;

typedef pair<int, int> II;
typedef vector<int> VI;
typedef vector<II> VII;
typedef vector<VI> VVI;
typedef vector<VII> VVII;

int test;
ull a,b,f[20][200] = {0}, g[20][200] = {0};

ull tinh(int r, ull x){
    if( r == 0) return 1;
    if( x == 0) return 0;
    int n = 0;
    ull y = 0, res = 0, T = 1;
    while(true){
        if( x < 10){
            for(int j = 0; j < x; j++) if( j <= r) res += g[n][r-j];
            break;
        }
        else{
            y += (x % 10) * T;
            x /= 10;
            T *= 10;
            n++;
        }
    }
    if(x <= r) res += tinh(r - x, y);
    return res;
}

ull tim(ull x){
    if(x == 0) return 0;
    ull res = 0;
    for(int i = 1; i < 200; i++){
        res += tinh(i, x/i);
    }
    return res;
}

int main(){
    //freopen("input.in","r",stdin);
    //freopen("output.out","w",stdout);

    f[0][0] = 1; g[0][0] = 1;
    for(int i = 0; i < 10; i++) f[1][i] = 1, g[1][i] = 1;
    for(int i = 2; i <= 19; i++){
        for(int j = 1; j < 10; j++){
            for(int k = j; k < 200; k++){
                f[i][k] += g[i-1][k-j];
            }
        }
        for(int j = 0; j < 200; j++) g[i][j] = g[i-1][j] + f[i][j];
    }


    //cout<<tim(10000);

    scanf("%d",&test);
    //test = 0;
    for(int itest = 0; itest < test; itest++){
        cin >> a >> b;
       // cout<< a <<"   "<<b<<endl;
        cout << tim(b) - tim(a - 1) << endl;
    }

}

Code mẫu của khuc_tuan

#include <iostream>
#include <cstdio>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <algorithm>
#include <cstring>
#include <cmath>
using namespace std;

#define Rep(i,n) for(int i=0;i<(n);++i)
#define For(i,a,b) for(int i=(a);i<=(b);++i)
#define Ford(i,a,b) for(int i=(a);i>=(b);--i)
#define fi first
#define se second
#define pb push_back
#define MP make_pair

typedef pair<int,int> PII;
typedef vector<int> VI;

int a[22],na;
long long T[22][200];

long long calc(long long X,int s){
    for(na=0;X>0;a[na++]=X%10,X/=10);
    if(na==0)return 0;
    int total=0,cur=0;
    Rep(i,na)total+=a[i];
    long long res=total==s;
    Ford(i,na-1,0) {
        Rep(j,a[i])if(s>=j+cur)res+=T[i][s-j-cur];
        cur+=a[i];
    }
    return res;
}

int main() {
    T[0][0]=1;
    For(i,1,20)For(j,0,199){
        Rep(ad,10)if(ad<=j)T[i][j]+=T[i-1][j-ad];   
    }
    int st;
    cin>>st;
    Rep(t,st){
        long long A,B,u,v,total=0;
        cin>>A>>B;
        For(s,1,162){
            u=A/s;
            if(u*s<A)++u;
            v=B/s;
            if(u<=v)total+=calc(v,s)-calc(u-1,s);
        }   
        cout<<total<<endl;
    }
    return 0;   
}