Leetcode#70Climbing Stairs

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?

分析，该问题类似于斐波那契序列问题，直观上采用递归来做，f(n)=f(n-1)+f(m-2)，然而时间复杂度太大，因此类似问题可以采用动态规划的思想，如下代码

public class Solution {

public int climbStairs(int n) {

if(n<=2)

return n;

else

{

int[] kinds=new int[n];

kinds[0]=1;

kinds[1]=2;

for(int i=2;i<n;i++)

{

kinds[i]=kinds[i-1]+kinds[i-2];

}

return kinds[n-1];

}

}

}