加一（动态规划）

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whiteawll 2022-08-16 14:46:50 博主文章分类：练习题目 ©著作权

文章标签 动态规划 c++ #define git ios 文章分类 后端开发

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#include<bits/stdc++.h>
using namespace std;

#define rep(i,l,r) for(int i=(l);i<=(r);i++)
#define per(i,l,r) for(int i=(l);i>=(r);i--)
#define ll long long
#define pii pair<int, int>
#define mset(s,t) memset(s,t,sizeof(t))
#define mcpy(s,t) memcpy(s,t,sizeof(t))
#define fi first
#define se second
#define pb push_back
#define all(x) (x).begin(),(x).end()
#define SZ(x) ((int)(x).size())
#define mp make_pair

const ll mod = 1e9 + 7;
//const ll mod = 998244353;

inline ll qmi (ll a, ll b) {
    ll ans = 1;
    while (b) {
        if (b & 1) ans = ans * a%mod;
        a = a * a %mod;
        b >>= 1;
    }
    return ans;
}
inline int read () {
    int x = 0, f = 0;
    char ch = getchar();
    while (!isdigit(ch)) f |= (ch=='-'),ch= getchar();
    while (isdigit(ch)) x = x * 10 + ch - '0', ch = getchar();
    return f?-x:x;
}
template<typename T> void print(T x) {
    if (x < 0) putchar('-'), x = -x;
    if (x >= 10) print(x/10);
    putchar(x % 10 + '0');
}
inline ll sub (ll a, ll b) {
    return ((a - b ) %mod + mod) %mod;
}
inline ll add (ll a, ll b) {
    return (a + b) %mod;
}
inline ll inv (ll a) {
    return qmi(a, mod - 2);
}
const int N  = 2e5 +11;

ll cnt[N][10][10];

void init () {
    for (int i = 0; i <= 9; i ++)
        cnt[0][i][i] = 1;
    for (int i = 0; i <= N - 9; i ++) {
        for (int j = 0; j <= 9; j ++)
        {
          for (int k = 0; k <= 8; k ++) {
             (cnt[i + 1][j][k + 1] += cnt[i][j][k])%mod;    
             cnt[i + 1][j][k + 1] %= mod;
          }
          (cnt[i + 1][j][0] += cnt[i][j][9])%mod;
          (cnt[i + 1][j][1] += cnt[i][j][9])%mod;
            
        }
    }
}
void solve() {
    ll n, m;
    n = read();
    m = read();
    string s = to_string(n);
    ll ans = 0;
    for (auto t : s) {
        for (int j = 0; j <= 9; j ++)
            {
                ans = (ans + cnt[m][t - '0'][j])%mod;
                if (ans < 0) ans += mod;
                if (ans >mod) ans -= mod;
            }
    }
    cout << ans << "\n";
}
signed main () {
    // ios::sync_with_stdio(0),cin.tie(0), cout.tie(0);
    init();
    int t;
    t =1;
    cin >> t;
    while (t --) solve();
    return 0;
}