LAB2.py

from typing import List
from CrowdScienceLab import colors
from Utils import drawGraph


NODE_N = 0
matrix = None # use matrix as static var.

# return list, list[i] = k means node i has k friends.
def friend_num() -> List[int]:
 li = []
 for i in range(0, NODE_N):
 k = 0
 for j in range(0, NODE_N):
 if i != j and matrix[i][j] == 1:
 k += 1
 li.append(k)
 return li

# This experiment studies the content of friendship paradox. 
# For moral considerations, one-side friends are not considered, 
# so undirected simple graph is adopted.

if __name__ == '__main__':
 NODE_N = int(input(f"\nPlease enter the {colors.BOLD}number of node{colors.ENDC} in the graph.\n"))
 print("Please enter the adjacent matrix")
 matrix = [list(map(int, input().split())) for i in range(NODE_N)]
 drawGraph(matrix)
 li = friend_num()
 up = 0
 for i in range(0, NODE_N):
 yes = 0
 aver = 0
 for j in range(0, NODE_N):
 if matrix[i][j] == 1 and i != j:
 aver += li[j]
 yes += 1
 aver /= yes
 if li[i] < aver:
 up += 1

 for i in range(0, NODE_N):
 print(f"Node\t{colors.BOLD}{i}{colors.ENDC}\thas\t{colors.BOLD}{li[i]}{colors.ENDC}\tfriends.")
 print(f"ratio that match the friendship paradox: {colors.BOLD}%.2f{colors.BOLD}" % (up / NODE_N))

 '''
 Result:
 
 Please enter the number of node in the graph.
 4
 Please enter the adjacent matrix
 0 1 1 0
 1 0 0 1
 1 1 0 1
 0 1 1 0
 Node	0	has	2	friends.
 Node	1	has	2	friends.
 Node	2	has	3	friends.
 Node	3	has	2	friends.
 ratio that match the friendship paradox: 0.50
 
 Process finished with exit code 0
 '''