leetcode_70题——Climbing Stairs（简单DP题）

Climbing Stairs

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Question  Solution 

 

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?

 

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  Dynamic Programming

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#include<iostream>

#include<vector>

using namespace std;

int climbStairs(int n) {

	if(n==0||n==1)

		return 1;

	int *ptr=new int[n+1];

	for(int i=0;i<n+1;i++)

		ptr[i]=0;

	ptr[n]=1;

	ptr[n-1]=1;

	for(int i=n-2;i>=0;i--)

		ptr[i]=ptr[i+1]+ptr[i+2];

	int last=ptr[0];

	delete []ptr;

	return last;

}

int main()

{

	cout<<climbStairs(3)<<endl;

}