题解

#include<iostream>
using namespace std;
int dp[1000] = {0};
int climb(int n){
dp[0] = 1;
dp[1] = 1;
dp[2] = 2;
for (int i = 2;i<=n;i++){
dp[i] = dp[i-1] + dp[i-2] + dp[i-3];
}
return dp[n];
}
int main(){
int n;
cin >> n;
cout << climb(n);
return 0;
}