300. Longest Increasing Subsequence
Category: /leetcodeGiven an integer array nums, return the length of the longest strictly increasing subsequence.
A subsequence is a sequence that can be derived from an array by deleting some or no elements without changing the order of the remaining elements. For example, [3,6,2,7] is a subsequence of the array [0,3,1,6,2,2,7].
Example 1:
Input: nums = [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.
Example 2:
Input: nums = [0,1,0,3,2,3]
Output: 4
Example 3:
Input: nums = [7,7,7,7,7,7,7]
Output: 1
Constraints:
1 <= nums.length <= 2500
-104 <= nums[i] <= 104
Solution
class Solution:
def lengthOfLIS(self, nums: List[int]) -> int:
sub = []
for num in nums:
i = bisect_left(sub, num)
# If num is greater than any element in sub
if i == len(sub):
sub.append(num)
# Otherwise, replace the first element in sub greater than or equal to num
else:
sub[i] = num
return len(sub)
If you are asked to implement bisect_left, do this
i, j = 0, len(sub)
while i != j:
m = (i + j) // 2
if sub[m] < num:
i = m + 1
else:
j = m
