上楼梯（递归+记忆化）

#include<stdio.h>#include<stdlib.h>#include<string.h>#include<algorithm>#include<iostream>using namespace std;long long n,f[100];long long dp(long long nn){if (f[nn]>0) return f[nn];f[nn]=dp(nn-1)+dp(nn-2);return (f[nn]);}int main(){memset(f,0,sizeof(f));f[0]=1;f[1]=1;scanf("%lld",&n);printf("%lld",dp(n));return 0;}