C++示範bitset取代hashset解Leetcode 1733 Minimum Number of People to Teach(含Py3 code)

C++示範bitset取代hashset解Leetcode 1733  Minimum Number of People to Teach

C++ STL的unordered_set與bitset都能解這題，但執行效率差很多，有誰寫C++其執行效能要比類似的Python code還要慢上好久倍?用hashset就如此

[Python code請進 ]

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C++ STL's unordered_set and bitset can both solve this problem, but their execution efficiency is very different. Has anyone written C++ that performs many times slower than similar Python code? This is the case with hashsets.

[codes on Leetcode]https://leetcode.com/problems/minimum-number-of-people-to-teach/solutions/7173816/bitset-is-good-0ms-beats-100/

class Solution:
    def minimumTeachings(self, n: int, languages: List[List[int]], friendships: List[List[int]]) -> int:
        know=[]
        for L in languages:
            know.append(set(L))
        
        need=set()
        for a1, b1 in friendships:
            a, b=a1-1, b1-1
            if know[a] & know[b]: continue
            need.add(a)
            need.add(b)
        
        if not need: return 0

        ans=float('inf')
        for lang in range(1, n+1):
            cnt=0
            for i in need:
                if lang not in know[i]: cnt+=1
            ans=min(ans, cnt)
        return ans