题解

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

const int MOD = 1000000007; // usaco玩多了

int main() {
    int n;
    cin >> n;
    
    vector<int> dp(n + 1);
    dp[0] = 1;  
    
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j < i / 2 + 1; j++) {
            dp[i] = (dp[i] + dp[j]) % MOD;
        }
        dp[i] = (dp[i] + 1) % MOD;
    }
    
    cout << dp[n] << endl;
    
    return 0;
}

真爱粉表示请求出战