init

4A.py

@@ -0,0 +1,30 @@
+import sys
+import math
+
+data = sys.stdin.read().split()
+n = int(data[0])
+xs = []
+ys = []
+idx = 1
+for _ in range(n):
+    xs.append(int(data[idx]))
+    ys.append(int(data[idx+1]))
+    idx += 2
+min_e = [float('inf')] * n
+used = [False] * n
+min_e[0] = 0.0
+ans = 0.0
+for _ in range(n):
+    v = -1
+    for i in range(n):
+        if not used[i] and (v == -1 or min_e[i] < min_e[v]):
+            v = i
+    used[v] = True
+    ans += math.sqrt(min_e[v])
+    vx, vy = xs[v], ys[v]
+    for u in range(n):
+        if not used[u]:
+            dist_sq = (xs[u] - vx)**2 + (ys[u] - vy)**2
+            if dist_sq < min_e[u]:
+                min_e[u] = dist_sq
+print(f"{ans:.10f}")