#7 反转整数，通过取余的方式分解反转字符顺序。还需要注意溢出场景处理

Author: Isaaclot

main/src/math/LC_7_ReverseInteger.java

@@ -0,0 +1,22 @@
+package math;
+
+/**
+ * @author [email protected]
+ * @since 2020/3/8 10:37 PM
+ */
+public class LC_7_ReverseInteger {
+    /**
+     * 思路：利用 取余数的方式取最后一个个位，取出的个位参与结果组装
+     */
+    public int reverse(int x) {
+        int rev = 0;
+        while (x != 0) {
+            int pop = x % 10;
+            x = x / 10;
+            if (rev > Integer.MAX_VALUE / 10 || (rev == Integer.MAX_VALUE / 10 && pop > 7)) return 0;
+            if (rev < Integer.MIN_VALUE / 10 || (rev == Integer.MIN_VALUE / 10 && pop < -8)) return 0;
+            rev = rev * 10 + pop;
+        }
+        return rev;
+    }
+}

main/test/math/LC_7_ReverseIntegerTest.java

@@ -0,0 +1,18 @@
+package math;
+
+import org.junit.Test;
+
+import static org.hamcrest.core.Is.is;
+import static org.junit.Assert.assertThat;
+
+/**
+ * @author [email protected]
+ * @since 2020/3/8 10:36 PM
+ */
+public class LC_7_ReverseIntegerTest {
+    @Test
+    public void reverse_integer_test() {
+        LC_7_ReverseInteger ri = new LC_7_ReverseInteger();
+        assertThat(ri.reverse(123), is(321));
+    }
+}

pom.xml

@@ -11,12 +11,6 @@
     <name>RicoNut</name>
     <description>RicoNut</description>
 
-    <parent>
-        <groupId>org.springframework.boot</groupId>
-        <artifactId>spring-boot-starter-parent</artifactId>
-        <version>2.0.4.RELEASE</version>
-        <relativePath/> <!-- lookup parent from repository -->
-    </parent>
 
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
@@ -25,10 +19,10 @@
     </properties>
 
     <dependencies>
-
         <dependency>
-            <groupId>org.springframework.boot</groupId>
-            <artifactId>spring-boot-starter-test</artifactId>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.12</version>
             <scope>test</scope>
         </dependency>
     </dependencies>