class Solution {

    public int combinationSum4(int[] nums, int target) {

       Arrays.sort(nums);

        int len=nums.length;

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

       dp[0]=1;             //就是设置成dp[0]=1!!!

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

            for(int j=0;j<len;j++){

                if(i>=nums[j])dp[i]+=dp[i-nums[j]];  //

            }

        }

        return dp[target];

    }

}