leetcode_300 Longest Increasing Subsequence(贪心+二分查找)

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

Example:

Input: [10,9,2,5,3,7,101,18]
Output: 4 

Explanation: The longest increasing subsequence is [2,3,7,101], therefore the length is 4.

思路：一个经典的题目，使用 bisect 库会更好写一些。巧妙之处在于 dp 数组的存储设计。
代码：

from bisect import bisect_left
class Solution:
    def lengthOfLIS(self, nums: [int]) -> int:
        dp = []
        for i in range(len(nums)):
            idx = bisect_left(dp, nums[i])
            if idx == len(dp):
                dp.append(nums[i])
            else:
                dp[idx] = nums[i]
        return len(dp)