provinces.py

class Solution:
    def findCircleNum(self, isConnected: List[List[int]]) -> int:
        count = 0
        length = len(isConnected)
        
        for i in range(length):
            if isConnected[i][i] == 1:
                count += 1
                self.dfs(i, length, isConnected)
        return count

    def dfs(self, i, length, matrix):
        if matrix[i][i] == 0:
            return 
        for j in range(length):
            if matrix[i][j] == 1:
                matrix[i][j] = 0
                self.dfs(j, length, matrix)