## 题目描述：

LeetCode 673. Number of Longest Increasing Subsequence

Given an unsorted array of integers, find the number of longest increasing subsequence.

Example 1:

```Input: [1,3,5,4,7]
Output: 2
Explanation: The two longest increasing subsequence are [1, 3, 4, 7] and [1, 3, 5, 7].
```

Example 2:

```Input: [2,2,2,2,2]
Output: 5
Explanation: The length of longest continuous increasing subsequence is 1, and there are 5 subsequences' length is 1, so output 5.
```

Note: Length of the given array will be not exceed 2000 and the answer is guaranteed to be fit in 32-bit signed int.

## Python代码：

``````class Solution(object):
def findNumberOfLIS(self, nums):
"""
:type nums: List[int]
:rtype: int
"""
maxLIS= ans = 0
size = len(nums)
dp = [1] * size
dz = [1] * size
for x in range(size):
for y in range(0, x):
if nums[x] > nums[y]:
if dp[y] + 1 > dp[x]:
dp[x] = dp[y] + 1
dz[x] = dz[y]
elif dp[y] + 1 == dp[x]:
dz[x] += dz[y]
maxLIS = max(dp + [0])
ans = 0
for p, z in zip(dp, dz):
if p == maxLIS:
ans += z
return ans
``````

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