From 09d448d17cfbd0a426df569c6957cffd6fdac743 Mon Sep 17 00:00:00 2001
From: bong6981 <kbk5190@naver.com>
Date: Tue, 12 Apr 2022 13:56:42 +0900
Subject: [PATCH] =?UTF-8?q?baekjoon/python/platinum2/q2261=5Fclosest=5Ftwo?=
 =?UTF-8?q?=5Fpoints(=EA=B0=80=EC=9E=A5=20=EA=B0=80=EA=B9=8C=EC=9A=B4=20?=
 =?UTF-8?q?=EB=91=90=20=EC=A0=90)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../java/src/silver4/Q1920_FindNumber.java    |  2 +
 .../platinum2/q2261_closest_two_points.py     | 53 +++++++++++++++++++
 2 files changed, 55 insertions(+)
 create mode 100644 baekjoon/java/src/silver4/Q1920_FindNumber.java
 create mode 100644 baekjoon/python/platinum2/q2261_closest_two_points.py

diff --git a/baekjoon/java/src/silver4/Q1920_FindNumber.java b/baekjoon/java/src/silver4/Q1920_FindNumber.java
new file mode 100644
index 00000000..8b067844
--- /dev/null
+++ b/baekjoon/java/src/silver4/Q1920_FindNumber.java
@@ -0,0 +1,2 @@
+package silver4;public class Q1920_FindNumber {
+}
diff --git a/baekjoon/python/platinum2/q2261_closest_two_points.py b/baekjoon/python/platinum2/q2261_closest_two_points.py
new file mode 100644
index 00000000..cfae0afb
--- /dev/null
+++ b/baekjoon/python/platinum2/q2261_closest_two_points.py
@@ -0,0 +1,53 @@
+# https://www.acmicpc.net/problem/2261
+import sys 
+input = sys.stdin.readline
+
+n = int(input().rstrip())
+points = []
+for _ in range(n):
+    x, y = map(int, input().split())
+    points.append((x, y))
+
+points.sort()
+
+def get_dis(p1, p2):
+    return (p1[0] - p2[0]) **2 + (p1[1] - p2[1]) **2
+
+def check_dis_all(start, end):
+    ans = 1e9
+    for i in range(start, end):
+        for j in range(i+1, end+1):
+            ans = min(ans, get_dis(points[i], points[j]))
+    return ans
+
+def cross_dis(start, mid, end, min_dis):
+    cands = []
+    for i in range(start, end+1):
+        dis = points[i][0] - points[mid][0]
+        if(dis ** 2 < min_dis):
+            cands.append(points[i])
+    
+    cands.sort(key=lambda x : x[1])
+
+    for i in range(len(cands)-1):
+        for j in range(i+1, len(cands)):
+            dis = cands[j][1] - cands[i][1]
+            if  dis ** 2 < min_dis:
+                min_dis = min(get_dis(cands[i], cands[j]), min_dis)
+            else:
+                break
+    return min_dis
+
+def find_min(start, end):
+    if end - start + 1 < 4:
+        return check_dis_all(start, end)
+
+    mid = (start + end) // 2
+    ans = min(find_min(start, mid), find_min(mid+1, end))
+    ans = min(ans, cross_dis(start, mid, end, ans))
+    return ans
+
+print(find_min(0, len(points)-1))
+
+
+