题解 | #N阶楼梯上楼问题#

#include <stdio.h>
typedef struct stack{
    int num;
    
}stack ;
int main() {
    int n;
    while (scanf("%d ", &n) != EOF) { 
        if(n==1){printf("1\n");continue;}
        if(n==2){
            printf("2\n");continue;;
        }
        int a[n+1];//用n表示索引为n的楼层有几种走法
        a[0]=1;
        a[1]=1;a[2]=2;
        for(int i=3;i<n+1;i++){
            a[i]=a[i-1]+a[i-2];
        }
        printf("%d\n",a[n]);
    }
    return 0;
}