记忆化搜索

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

int dp[1000005];

int f(int n) {
	if (dp[n] != -1) return dp[n];
	if (n == 1) return 1;
	int ans = 0;
	for (int i = 1; i <= n / 2; i++) {
		ans += f(i);
	}
	dp[n] = ans + 1;
	return dp[n];
}

int main() {
	int n;
	cin >> n;
	memset(dp,-1,sizeof(dp));
	cout << f(n);
	return 0;
}