Happy Students — LeetCode 2860 Python Solution

The problem

You are given a 0-indexed integer array nums of length n where n is the total number of students in the class. The class teacher tries to select a group of students so that all the students remain happy.

Example

Input

nums = [1,1]

Output

2

Explanation

The two possible ways are:

Python solution

class Solution:
    def countWays(self, nums: List[int]) -> int:
        nums.sort()
        n = len(nums)
        ans = 0
        for i in range(n + 1):
            if i and nums[i - 1] >= i:
                continue
            if i < n and nums[i] <= i:
                continue
            ans += 1
        return ans

Complexity

Pattern: Sorting

Spend O(n log n) once to buy an ordering that makes the rest of the problem trivial. LeetCode 2860. Happy Students is filed here because LeetCode tags it Sorting, which is the vocabulary this hub collects.

The sorting guide has the Python template for the pattern and the 401 LeetCode problems that use it.

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