2024-05-18

tgyuuAn/README.md

@@ -55,4 +55,5 @@
 | 51차시 | 2023.04.07 |  BFS  | <a href="https://www.acmicpc.net/problem/5213">과외맨</a> | https://github.com/AlgoLeadMe/AlgoLeadMe-1/pull/179
 | 52차시 | 2023.05.06 |  위상정렬  | <a href="https://www.acmicpc.net/problem/1516">게임 개발</a> | https://github.com/AlgoLeadMe/AlgoLeadMe-1/pull/182
 | 53차시 | 2023.05.09 |  백트래킹  | <a href="https://www.acmicpc.net/problem/12100">2048 (Easy)</a> | https://github.com/AlgoLeadMe/AlgoLeadMe-1/pull/184
+| 55차시 | 2023.05.18 |  유니온 파인드  | <a href="https://www.acmicpc.net/problem/4195">친구 네트워크</a> | https://github.com/AlgoLeadMe/AlgoLeadMe-1/pull/189
 ---

tgyuuAn/유니온 파인드/친구 네트워크.py

@@ -0,0 +1,40 @@
+import sys
+from collections import defaultdict
+
+def input(): return sys.stdin.readline().rstrip()
+
+def find_parent(element, graph):
+    if graph[element] == element: return element
+
+    parent = graph[element]
+    graph[element] = find_parent(parent, graph)
+    return graph[element]
+
+def union(first, second, graph, count):
+    x = find_parent(first, graph)
+    y = find_parent(second, graph)
+
+    if x == y: return
+
+    x, y = min(x, y), max(x, y)
+    graph[y] = x
+    count[x] += count[y]
+    count[y] = 0
+    return
+
+T = int(input())
+
+for _ in range(T):
+    F = int(input())
+    index = 1
+    parent = defaultdict(str)
+    count = defaultdict(lambda : 1)
+
+    for _ in range(F):
+        first, second = input().split()
+        if parent[first] == "": parent[first] = first
+        if parent[second] == "": parent[second] = second
+        if parent[first] != parent[second]: union(first, second, parent, count)
+
+        print(count[find_parent(first, parent)])
+