leetcode do question notes 70

Suppose you are climbing stairs. You need  n steps to get to the top of the building.

Every time you can climb  1 or  2 a step. How many different ways can you get to the top of the building?

Idea 1: Recursion

int climbStairs(int n){
    int num[n+1];
    num[0]=1,num[1]=1;
    for(int i=2;i<=n;i++){
        num[i]=num[i-1]+num[i-2];
    }
    return num[n];
}

analyze:

The method of the next step of this question is equal to the number of methods of the previous step plus the first two steps, and recurses continuously to n to get the answer

Summarize:

This question examines the application of recursion, and it can be solved by converting the step problem into a recursive problem