Codeforces 414-B. Mashmokh and ACM(数位dp)

Codeforces 414-B. Mashmokh and ACM

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• 是一道数位dp，我还是dp太菜了，多做题吧，具体的写在code里面了

#include<bits/stdc++.h>
using namespace std;
#pragma GCC optimize(2)
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;

const int mod = 1e9 + 7;
int n, k;
const int N = 2e3 + 10;
int dp[N][N];
vector<int>g[N];

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
    cin >> n >> k;
    for (int i = 1; i <= n; ++i) {
        for (int j = 1; j <= n; ++j) {
            if (i * j > n) break;
            g[i].push_back(i * j);
        }
    }
    for (int i = 1; i <= n; ++i) dp[1][i] = 1;
    //dp[i][j] i目前有几个数字,j最后一个数字是多少
    for (int i = 1; i <= k; ++i) {
        for (int j = 1; j <= n; ++j) {
            for (int p = 0; p < g[j].size(); ++p) {
                dp[i + 1][g[j][p]] += dp[i][j] % mod;
                dp[i + 1][g[j][p]] %= mod;
            }
        }
    }
    int ans = 0;
    for (int i = 1; i <= n; ++i) {
        ans += dp[k][i] % mod;
        ans %= mod;
    }
    cout << ans % mod << "
";
    return 0;
}