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Merge pull request youngyangyang04#2750 from suinming/kamacoder-109-py

feat: 109. 冗余连接II新增python解法

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- 0109.冗余连接II.md

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`‎problems/kamacoder/0109.冗余连接II.md`

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`@@ -351,6 +351,92 @@ public class Main {`
`351`	`351`	```
`352`	`352`	`### Python`
`353`	`353`
	`354`	+```python
	`355`	`+from collections import defaultdict`
	`356`	`+`
	`357`	`+father = list()`
	`358`	`+`
	`359`	`+`
	`360`	`+def find(u):`
	`361`	`+ if u == father[u]:`
	`362`	`+ return u`
	`363`	`+ else:`
	`364`	`+ father[u] = find(father[u])`
	`365`	`+ return father[u]`
	`366`	`+`
	`367`	`+`
	`368`	`+def is_same(u, v):`
	`369`	`+ u = find(u)`
	`370`	`+ v = find(v)`
	`371`	`+ return u == v`
	`372`	`+`
	`373`	`+`
	`374`	`+def join(u, v):`
	`375`	`+ u = find(u)`
	`376`	`+ v = find(v)`
	`377`	`+ if u != v:`
	`378`	`+ father[u] = v`
	`379`	`+`
	`380`	`+`
	`381`	`+def is_tree_after_remove_edge(edges, edge, n):`
	`382`	`+ # 初始化并查集`
	`383`	`+ global father`
	`384`	`+ father = [i for i in range(n + 1)]`
	`385`	`+`
	`386`	`+ for i in range(len(edges)):`
	`387`	`+ if i == edge:`
	`388`	`+ continue`
	`389`	`+ s, t = edges[i]`
	`390`	`+ if is_same(s, t): # 成環,即不是有向樹`
	`391`	`+ return False`
	`392`	`+ else: # 將s,t放入集合中`
	`393`	`+ join(s, t)`
	`394`	`+ return True`
	`395`	`+`
	`396`	`+`
	`397`	`+def get_remove_edge(edges):`
	`398`	`+ # 初始化并查集`
	`399`	`+ global father`
	`400`	`+ father = [i for i in range(n + 1)]`
	`401`	`+`
	`402`	`+ for s, t in edges:`
	`403`	`+ if is_same(s, t):`
	`404`	`+ print(s, t)`
	`405`	`+ return`
	`406`	`+ else:`
	`407`	`+ join(s, t)`
	`408`	`+`
	`409`	`+`
	`410`	`+if __name__ == "__main__":`
	`411`	`+ # 輸入`
	`412`	`+ n = int(input())`
	`413`	`+ edges = list()`
	`414`	`+ in_degree = defaultdict(int)`
	`415`	`+`
	`416`	`+ for i in range(n):`
	`417`	`+ s, t = map(int, input().split())`
	`418`	`+ in_degree[t] += 1`
	`419`	`+ edges.append([s, t])`
	`420`	`+`
	`421`	`+ # 尋找入度為2的邊,並紀錄其下標(index)`
	`422`	`+ vec = list()`
	`423`	`+ for i in range(n - 1, -1, -1):`
	`424`	`+ if in_degree[edges[i][1]] == 2:`
	`425`	`+ vec.append(i)`
	`426`	`+`
	`427`	`+ # 輸出`
	`428`	`+ if len(vec) > 0:`
	`429`	`+ # 情況一:刪除輸出順序靠後的邊`
	`430`	`+ if is_tree_after_remove_edge(edges, vec[0], n):`
	`431`	`+ print(edges[vec[0]][0], edges[vec[0]][1])`
	`432`	`+ # 情況二:只能刪除特定的邊`
	`433`	`+ else:`
	`434`	`+ print(edges[vec[1]][0], edges[vec[1]][1])`
	`435`	`+ else:`
	`436`	`+ # 情況三: 原圖有環`
	`437`	`+ get_remove_edge(edges)`
	`438`	+```
	`439`	`+`
`354`	`440`	`### Go`
`355`	`441`
`356`	`442`	`### Rust`

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