From 4d8d45e95b3e8a01c82ea30de8bc733e5d34a863 Mon Sep 17 00:00:00 2001
From: pn43tqvrm <2516333959@qq.com>
Date: Sat, 19 Feb 2022 16:12:56 +0800
Subject: [PATCH] =?UTF-8?q?Add=20=E4=BA=8C=E5=88=86=E6=8E=92=E5=BA=8F?=
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---
 二分排序 | 44 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)
 create mode 100644 二分排序

diff --git a/二分排序 b/二分排序
new file mode 100644
index 0000000..6ef9fde
--- /dev/null
+++ b/二分排序
@@ -0,0 +1,44 @@
+//二分法 
+// 整数二分
+bool check(int x) {/* ... */} // 检查x是否满足某种性质
+
+// 区间[l, r]被划分成[l, mid]和[mid + 1, r]时使用：
+int bsearch_1(int l, int r)
+{
+    while (l < r)
+    {
+        int mid = l + r >> 1;
+        if (check(mid)) r = mid;    // check()判断mid是否满足性质
+        else l = mid + 1;
+    }
+    return l;
+}
+// 区间[l, r]被划分成[l, mid - 1]和[mid, r]时使用：
+int bsearch_2(int l, int r)
+{
+    while (l < r)
+    {
+        int mid = l + r + 1 >> 1;
+        if (check(mid)) l = mid;
+        else r = mid - 1;
+    }
+    return l;
+}
+ 
+
+// 浮点数二分
+bool check(double x) {/* ... */} // 检查x是否满足某种性质
+
+double bsearch_3(double l, double r)
+{
+    const double eps = 1e-6;   // eps 表示精度，取决于题目对精度的要求
+    while (r - l > eps)
+    {
+        double mid = (l + r) / 2;
+        if (check(mid)) r = mid;
+        else l = mid;
+    }
+    return l;
+}
+
+//复杂度说明： 时间复杂度为o(logn). 
\ No newline at end of file