You are given n pairs of numbers. In every pair, the first number is always smaller than the second number.
Now, we define a pair (c, d) can follow another pair (a, b) if and only if b < c. Chain of pairs can be formed in this fashion.
Given a set of pairs, find the length longest chain which can be formed. You needn‘t use up all the given pairs. You can select pairs in any order.
Example 1:
Input: [[1,2], [2,3], [3,4]] Output: 2 Explanation: The longest chain is [1,2] -> [3,4]
Note:
- The number of given pairs will be in the range [1, 1000].
class Solution:def findLongestChain(self, pairs):""":type pairs: List[List[int]]:rtype: int"""res = 0sortedPairs = sorted(pairs, key=lambda x: (x[0], x[1]))pre = -2147483648for pair in sortedPairs:if pre < pair[0]:res += 1pre = pair[1]elif pair[1] < pre:pre = pair[1]return res#pairs = [[1, 2], [2, 3], [5, 2], [3, 4], [3, 10]]pairs = [[-6, 9], [1, 6], [8, 10], [-1, 4], [-6, -2], [-9, 8], [-5, 3], [0, 3]]s = Solution()res = s.findLongestChain(pairs)print(res)
