Nine degrees OJ 1205 N-Step stairs Upstairs problem (DP)

Topic 1205:n Stair Stairs upstairs problem

time limit:1 seconds

Memory limit:128 MB

Special question: No

submitted:2817

Resolution:1073

Title Description:

N-Step stairs upstairs problem: one can walk two or one order, ask how many kinds of way upstairs. (Non-recursive requirements apply)

Input:

The input includes an integer N, (1<=n<90).

Output:

There may be multiple sets of test data, for each set of data,
The number of ways to go upstairs when the stair order is n.

Sample input:

4

Sample output:

5

Basic ideas:
Go to the nth order may be from the first step to the n-1, or from the n-2 order to go two steps,
Set F (n) as the number of walks to the n order, then the state transfer equation is
F (n) =f (n-1) +f (n-2).

#include <stdio.h> #include <string.h>long long f[100];int main (int argc, char *argv[]) {    int n;    while (~SCANF ("%d", &n))    {        memset (f,0,sizeof (f));        F[0]=f[1]=1;        for (int i=2;i<=n;++i)            f[i]=f[i-1]+f[i-2];        printf ("%lld\n", F[n]);    }    return 0;}

Nine degrees OJ 1205 N-Step stairs Upstairs problem (DP)