跳台阶

public class Solution {    public int JumpFloor(int target) {        if (target == 1)            return 1;        if (target == 2)            return 2;        int[] array = new int [target + 1];        array[1] = 1;        array[2] = 2;        for (int i = 3; i <= target; i++)            array[i] = array[i-1] + array[i-2];        return array[target];    }}