673. Number of Longest Increasin

https://leetcode.com/problems/number-of-longest-increasing-subsequence/description/

class Solution {
public int findNumberOfLIS(int[] nums) {

    if(nums == null || nums.length == 0) return 0;
    int len = nums.length;
    int[] dp = new int[len];
    int[] sum = new int[len];
    Arrays.fill(dp, 1); Arrays.fill(sum, 1);
    int res = 1, maxLen = 1;
    for(int i = 1; i < len; i++){
        for(int j = i - 1; j >= 0; j--){
            if(nums[i] > nums[j]){
                if(dp[i] == dp[j]  + 1)
                    sum[i] += sum[j];
                if(dp[i] < dp[j]  + 1){
                    dp[i] = dp[j] + 1;
                    sum[i] = sum[j];
                }
            }
        }
        if(maxLen == dp[i]) res += sum[i];
        if(maxLen < dp[i]){
            maxLen = dp[i];
            res = sum[i];
        }
    }
    return res;
}

}