From ef74e4045628399275386dfddef4e95374238efe Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=9C=B1=E6=96=87=E8=B5=B5?= <1392936858@qq.com>
Date: Sat, 25 Apr 2020 23:49:39 +0800
Subject: [PATCH] =?UTF-8?q?=E5=88=A4=E6=96=AD=E6=98=AF=E5=90=A6=E6=98=AF?=
 =?UTF-8?q?=E8=B4=A8=E6=95=B0?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../algorithmsfourthedition/Chapter01.java    | 41 +++++++++++++++++++
 1 file changed, 41 insertions(+)
 create mode 100644 src/main/java/com/ximo/datastructuresinaction/algorithmsfourthedition/Chapter01.java

diff --git a/src/main/java/com/ximo/datastructuresinaction/algorithmsfourthedition/Chapter01.java b/src/main/java/com/ximo/datastructuresinaction/algorithmsfourthedition/Chapter01.java
new file mode 100644
index 0000000..88f96fc
--- /dev/null
+++ b/src/main/java/com/ximo/datastructuresinaction/algorithmsfourthedition/Chapter01.java
@@ -0,0 +1,41 @@
+package com.ximo.datastructuresinaction.algorithmsfourthedition;
+
+/**
+ * @author xikl
+ * @date 2020/4/25
+ */
+public class Chapter01 {
+
+    public static boolean isPrime(int n) {
+        // 大于1的数字才是
+        if (n < 2) {
+            return false;
+        }
+
+        // 2 和 3 本身只有1和本身
+        if (n == 2 || n == 3) {
+            return true;
+        }
+
+        // 排除偶数
+        if (n % 2 == 0) {
+            return false;
+        }
+
+        // 根据定理
+        // 避免求根号，改为平方
+        for (int i = 2; i * i <= n; i++) {
+            if (n % i == 0) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    public static void main(String[] args) {
+        System.out.println(isPrime(13));
+    }
+
+
+}