👑 G4-20040

Author: jyh071116

👑 G4/20040.py

@@ -0,0 +1,25 @@
+import sys
+input = sys.stdin.readline
+sys.setrecursionlimit(10**6)
+
+n, m = map(int, input().split())
+parent = [i for i in range(n)]
+def find(x):
+  if x == parent[x]: return x
+  parent[x] = find(parent[x])
+  return parent[x]
+
+def union(x, y):
+  x = find(x)
+  y = find(y)
+  if x != y:
+    parent[x] = y
+
+for i in range(1, m+1):
+  x, y = map(int, input().split())
+  if find(x) == find(y):
+    print(i)
+    break
+  union(x, y)
+else:
+  print(0)