题解

#include <iostream>
#include <vector>
using namespace std;

int main() {
    int n, m;
    cin >> n >> m;
    
    vector<int> dp(n, 0);
    dp[0] = 1;  // 初始状态
    
    for (int i = 1; i <= m; i++) {
        vector<int> new_dp(n, 0);
        for (int j = 0; j < n; j++) {
            new_dp[j] = dp[(j-1+n)%n] + dp[(j+1)%n];
        }
        dp = new_dp;
    }
    
    cout << dp[0] << endl;
    return 0;
}