Description

Suppose you have a random list of people standing in a queue. Each person is described by a pair of integers (h, k), where h is the height of the person and k is the number of people in front of this person who have a height greater than or equal to h. Write an algorithm to reconstruct the queue.

Note: The number of people is less than 1,100.

Example

Input:
[[7,0], [4,4], [7,1], [5,0], [6,1], [5,2]]

Output:
[[5,0], [7,0], [5,2], [6,1], [4,4], [7,1]]

Solutions

1. Greedy

# Time: O(n^2)
# Space: O(n)
class Solution:
    def reconstructQueue(self, people: List[List[int]]) -> List[List[int]]:
        people = sorted(people, key = lambda x: (-x[0], x[1]))

        res = []
        for p in people:
            res.insert(p[1], p)
        return res

# 37/37 cases passed (96 ms)
# Your runtime beats 84.54 % of python3 submissions
# Your memory usage beats 100 % of python3 submissions (13 MB)

References

  1. 406. Queue Reconstruction by Height
  2. Easy concept with Python/C++/Java Solution
  3. Python Solution