动态规划

public class Solution {
    public int jumpFloorII(int target) {
        if(target <= 2){
            return target;
        }

        int[] dp = new int[target+1];
        dp[0] = 0;


        for (int i = 1; i <= target; i++) {

            int j = i - 1;
            dp[i] = 1;
            while (j >= 1){

                dp[i] += dp[j];
                j--;
            }

        }

        return dp[target];        
    }
}