Climbing Stairs

Description

You are climbing a stair case. It takes n steps to reach to the top.

Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?

Example
Given an example n=3 , 1+1+1=2+1=1+2=3
return 3

Link

Lintcode_ladder

Method

1. Permutation version of backpack
2. x

Example

1. 1

class Solution {
public:
    /**
     * @param n: An integer
     * @return: An integer
     */
    int climbStairs(int n) {
        // write your code here
        int cur = 1;
        int prev =0;
        for (int i = 1; i < n+1; ++i) {
            int tmp = cur + prev;
            prev = cur;
            cur = tmp;
        }
        return cur;
    }
};

Similar problems

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