LeetCode OJ：Climbing Stairs（攀爬台阶）

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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简单的dp问题，代码如下：

 class Solution {
 public:
     int climbStairs(int n) {
           if(n <= )
               return n;
           dp.resize(n + );
           dp[] = ;
           dp[] = ;
           for(int i = ; i < n + ; ++i){
               dp[i] += dp[i - ];
               dp[i] += dp[i - ];
           }
           return dp[n];
     }
 private:
     vector<int> dp;
 };

java版本代码如下所示：

 public class Solution {
     public int climbStairs(int n) {
         if(n < ) return n;
         int dp [] = new int [n+];
         dp[] = ;
         dp[] = ;
         for(int i = ; i <= n; ++i){
             dp[i] = dp[i-] + dp[i-];
         }
         return dp[n];
     }
 }